Medicine

Medicine. \- The science of medicine, as we understand it, has for its province the treatment of disease. The word "medicine" (Lat. medicina: sc. ars, art of healing, from mederi, to heal) may be used very widely, to include Pathology, the theory of the causation of disease, or, very narrowly, to mean only the drug or form of remedy prescribed by the physician - this being more properly the subject of Therapeutics (q.v.) and Pharmacology. But it is necessary in practice, for historical comprehensiveness, to keep the wider meaning in view.

Disease (see Pathology) is the correlative of health, and the word is not capable of a more penetrating definition. From the time of Galen, however, it has been usual to speak of the life of the body either as proceeding in accordance with nature (Kara Ou6cv, secundum naturam) or as overstepping the bounds of nature (irapa OvQCV, praeter naturam). Taking disease to be a deflexion from the line of health, the first requisite of medicine is an extensive and intimate acquaintance with the norm of the body. The structure and functions of the body form the subject of Anatomy (q.v.) and Physiology.  The medical art (ars medendi) divides itself into departments and subdepartments. The most fundamental division is into internal and external medicine, or into medicine proper and surgery. The treatment of wounds, injuries and deformities, with operative interference in general, is the special department of surgical practice (the corresponding parts of pathology, including inflammation, repair, and removable tumours, are sometimes grouped together as surgical pathology); and where the work of the profession is highly subdivided, surgery becomes the exclusive province of the surgeon, while internal medicine remains to the physician. A third great department of practice is formed by obstetric medicine or midwifery (see Obstetrics); and dentistry, or dental surgery, is given up to a distinct branch of the profession.

A state of war, actual or contingent, gives occasion to special developments of medical and surgical practice (military hygiene and military surgery). Wounds caused by projectiles, sabres, &c., are the special subject of naval and military surgery; while under the head of military hygiene we may include the general subject of ambulances, the sanitary arrangements of camps, and the various forms of epidemic camp sickness.

The administration of the civil and criminal law involves frequent relations with medicine, and the professional subjects most likely to arise in that connexion, together with a summary of causes celebres, are formed into the department of Medical Jurisprudence.

In preserving the public health, the medical profession is again brought into direct relation with the state, through the public medical officers.

History Of Medicine Medicine a Portrayed in the Homeric Poems. - In the state of society pictured by Homer it is clear that medicine has already had a history. We find a distinct and organized profession; we find a system of treatment, especially in regard to injuries, which it must have been the work of long experience to frame; we meet with a nomenclature of parts of the body substantially the same (according to Daremberg) as that employed long afterwards in the writings of Hippocrates; in short, we find a science and an organization which, however imperfect as compared with those of later times, are yet very far from being in their beginning. The Homeric heroes themselves are repre sented as having considerable skill in surgery, and as able to attend to ordinary wounds and injuries, but there is also a professional class, represented by Machaon and Podalirius, the two sons of Asclepius, who are treated with great respect. It would appear, too, from the Aethiopis of Archinus (quoted by Welcker and Haser) that the duties of these two were not precisely the same. Machaon's task was more especially to heal injuries, while Podalirius had received from .his father the gift of "recognizing what was not visible to the eye, and tending what could not be healed." In other words, a rough indication is seen of the separation of medicine and surgery. Asclepius appears in Homer as a Thessalian king, not as a god, though.in later times divine honours were paid to him. There is no sign in the Homeric poems of the subordination of medicine to religion which is seen in ancient Egypt and India, nor are priests charged, as they were in those countries, with medical functions - all circumstances which throw grave doubts on the commonly received opinion that medicine derived its origin in all countries from religious observances.

Although the actual organization of medicine among the Homeric Greeks was thus quite distinct from religion, the worship of Asclepius (or Aesculapius) as the god of healing demands some notice. This cult spread very widely among the Greeks; it had great civil importance, and lasted even into Christian times; but there is no reason to attribute to it any special connexion with the development of the science or profession of medicine. Sick persons repaired, or were conveyed, to the temples of Asclepius in order to be healed, just as in modern times relief is sought by a devotional pilgrimage or from the waters of some sacred spring, and then as now the healing influence was sometimes sought by deputy. The sick person, or his representative, after ablution, prayer and sacrifice, was made to sleep on the hide of the sacrificed animal, or at the feet of the statue of the god, while sacred rites were performed. In his sleep (incubatio, 1yuou / 7 ra) the appropriate remedy was indicated by a dream. Moral or dietetic remedies were more often prescribed than drugs. The record of the cure was inscribed on the columns or walls of the temple; and it has been thought that in this way was introduced the custom of "recording cases," and that the physicians of the Hippocratic school thus learnt to accumulate clinical experience. But the priests of Asclepius were not physicians. Although the latter were often called Asclepiads, this was in the first place to indicate their real or supposed descent from Asclepius, and in the second place as a complimentary title. No medical writing of antiquity speaks of the worship of Asclepius in such a way as to XVIII. 2 a imply any connexion with the ordinary art of healing. The two systems appear to have existed side by side, but to have been distinct, and if they were ever united it must have been before the times of which we have any record. The theory of a development of Greek medicine from the rites of Asclepius, though defended by eminent names, must accordingly be rejected.

## Development of Medicine in Greece

It is only from non medical writers that anything is known of the development of medicine in Greece before the age of Hippocrates. The elaborate collections made by Daremberg of medical notices in the poets and historians illustrate the relations of the profession to society, but do little to prepare us for the Hippocratic period. Nor is much importance to be attached to the influence of the philosophical sects on medicine except as regards the school of Pythagoras. That philosopher and several of his successors were physicians, but we do not know in what relation they stood to later medical schools. We must therefore hasten onward to the age of Pericles, in which Hippocrates, already called "the Great," was in medicine as complete a representative of the highest efforts of the Greek intellect as were his contemporaries the great philosophers, orators and tragedians. The medical art as we now practise it, the character of the physician as we now understand it, both date for us from Hippocrates. The justification of this statement is found in the literary collection of writings known by his name. Of these certainly many are falsely ascribed to the historical Hippocrates of Cos; others are almost as certainly rightly so ascribed; others again are clearly works of his school, whether from his hand or not. But which are to be regarded as the "genuine works" is still uncertain, and authorities are conflicting. There are clearly two schools represented in the collection - that of Cnidus in a small proportion, and that of Cos in far the larger number of the works. The latter was that to which Hippocrates belonged, and where he gave instruction; and accordingly it may be taken that works of this school, when not obviously of a different date, are Hippocratic in doctrine if not in actual authorship.

## Hippocratic Medicine

The first grand characteristic of Hippocratic medicine is the high conception of the duties and status of the physician, shown in the celebrated "Oath of Hippocrates" and elsewhere - equally free from the mysticism of a priesthood and the vulgar pretensions of a mercenary craft. So matured a professional sentiment may perhaps have been more the growth of time and organization than the work of an individual genius, but certainly corresponds with the character universally attributed to Hippocrates himself. The second great quality is the singular artistic skill and balance with which the Hippocratic physician used such materials and tools as he possessed. Here we recognize the true Greek But this artistic completeness was closely connected with the third cardinal virtue of Hippocratic medicine - the clear recognition of disease as being equally with life a process governed by what we should now call natural laws, which could be known by observation, and which indicated the spontaneous and normal direction of recovery, by following which alone could the physician succeed. In the fourth place, these views of the "natural history of disease" (in modern language) led to habits of minute observation and accurate interpretation of symptoms, in which the Hippocratic school was unrivalled in antiquity, and has been the model for all succeeding ages, so that even in these days, with our enormous advances in knowledge, the true method of clinical medicine may be said to be the method of Hippocrates.

The actual science of the Hippocratic school was of course very limited. In anatomy and physiology little advance had been made, and so of pathology in the sense of an explanation of morbid processes or knowledge of diseased structures there could be very little. The most valuable intellectual possession was a large mass of recorded observations in individual cases and epidemics of disease. Whether these observations were systematic or individual, and how they were recorded, are points of which we are quite ignorant, as the theory that the votive tablets in the temples supplied such materials must be abandoned.

Though the Hippocratic medicine was so largely founded on observation, it would be an error to suppose that dogma or theory had no place. The dominating theory of disease was the humoral, which has never since ceased to influence medical thought and practice. According to this celebrated theory, the body contains four humours - blood, phlegm, yellow bile and black bile, a right proportion and mixture of which constitute health; improper proportions or irregular distribution, disease. It is doubtful whether the treatise in which this theory is fully expounded is as old as Hippocrates himself; but it was regarded as a Hippocratic doctrine, and, when taken up and expanded by Galen, its terms not only became the common property of the profession, but passed into general literature and common language. Another Hippocratic doctrine, the influence of which is not even yet exhausted, is that of the healing power of nature. Not that Hippocrates taught, as he was afterwards reproached with teaching, that nature is sufficient for the cure of diseases; for he held strongly the efficacy of art. But he recognized, at least in acute diseases, a natural process which the humours went through - being first of all crude, then passing through coction or digestion, and finally being expelled by resolution or crisis through one of the natural channels of the body. The duty of the physician was to foresee these changes, "to assist or not to hinder them," so that "the sick man might conquer the disease with the help of the physician." The times at which crises were to be expected were naturally looked for with anxiety; and it was a cardinal point in the Hippocratic system to foretell them with precision. Hippocrates, influenced as is thought by the Pythagorean doctrines of number, taught that they were to be expected on days fixed by certain numerical rules, in some cases on odd, in others on even numbers - the celebrated doctrine of "critical days." This false precision can have had no practical value, but may have enforced habits of minute observation. It follows from what has been said that prognosis, or the art of foretelling the course and event of the disease, was a strong point with the Hippocratic physicians. In this they have perhaps never been excelled. Diagnosis, or recognition of the disease, must have been necessarily imperfect, when no scientific nosology or system of disease existed, and the knowledge of anatomy was quite inadequate to allow of a precise determination of the seat of disease; but symptoms were no doubt observed and interpreted skilfully. The pulse is not spoken of in any of the works now attributed to Hippocrates himself, though it is mentioned in other works of the collection.

In the treatment of disease, the Hippocratic school attached great importance to diet, the variations necessary in different diseases being minutely defined. Medicines were regarded as of secondary importance, but not neglected, two hundred and sixty-five drugs being mentioned at different places in the Hippocratic works. Blood-letting was known, but not greatly practised. The highest importance was attached to applying all remedies at the right moment, and the general principle enforced of making all influences - internal and external - co-operate for the relief of the patient. The principles of treatment just mentioned apply more especially to the cure of acute diseases; but they are the most salient characteristics of the Hippocratic school. In chronic cases diet, exercise and natural methods were chiefly relied upon.

The school of Cnidus, as distinguished from that of Cos, of which Hippocrates is the representative, appears to have differed in attaching more importance to the differences of special diseases, and to have made more use of drugs. A treatise on the diseases of women, contained in the Hippocratic collection, and of remarkable practical v alue, is attributed to this school.

The above sketch of Hippocratic medicine will make it less necessary to dwell upon the details relating to subsequent medical schools or sects in ancient times. The general conception of the physician's aim and task remained the same, though, as knowledge increased, there was much divergence both in theory and practice - even opposing schools were found to be developing some part of the Hippocratic system. Direct opponents or repudiators of the authority of Hippocrates were rare, all generally appealing to his authority. But, insensibly, the least valuable part of the Hippocratic work, the theory, was made permanent; the most valuable, the practical, neglected.

## Post-Hippocratic Medicine

After Hippocrates the progress of medicine in Greece does not call for any special remark in such a sketch as this, but mention must be made of one great name. Though none of Aristotle's writings are strictly medical, he has by his researches in anatomy and physiology contributed greatly to the progress of medicine. It should also be remembered that he was of an Asclepiad family, and received that partly medical education which was traditional in such families, and also himself is said to have practised medicine as an amateur. Moreover, his works on natural history doubtless furthered the progress among the Greeks of sciences tributary to medicine, though the only specimens of such works which have come down to us from the Peripatetic school are those of Theophrastus, who may be considered the founder of the scientific study of botany. Among his encyclopaedic writings were some on medical subjects, of which fragments only have been preserved. The Peripatetic school may have been more favourable to the development of medicine, as of other departments of natural knowledge, than any other; but there is no evidence that any of the philosophical schools had important influence on the progress of medicine. The fruit of Aristotle's teaching and example was seen later on in the schools of Alexandria.

The century after the death of Hippocrates is a time almost blank in medical annals. It is probable that the science, like others, shared in the general intellectual decline of Greece after the Macedonian supremacy; but the works of physicians of the period are almost entirely lost, and were so even in the time of Galen. Galen classes them all as of the dogmatic school; but, whatever may have been their characteristics, they are of no importance in the history of the science.

## Alexandrian School of Medicine

The dispersion of Greek science and intellectual activity through the world by the conquests of Alexander and his successors led to the formation of more than one learned centre, in which medicine among other sciences was represented. Pergamum was early distinguished for its medical school; but in this as in other respects its reputation was ultimately effaced by the more brilliant fame of Alexandria. It is here that the real continuation and development of Hippocratic medicine can be traced.

In one department the Alexandrian school rapidly surpassed its Greek original - namely, in the study of anatomy. The dissection of the human body, of which some doubtful traces or hints only are found in Greek times, was assiduously carried out, being favoured or even suggested perhaps by the Egyptian custom of disembowelling and embalming the bodies of the dead. There is no doubt that the organs were also examined by opening the bodies of living persons - criminals condemned to death being given over to the anatomists for this purpose.

Two eminent names stand in the first rank as leaders of the two earliest schools of medicine which arose in Alexandria, Herophilus and Erasistratus.

Herophilus (335-280 B.C.) was a Greek of Chalcedon, a pupil of the schools both of Cos and of Cnidus. He was especially noted for his profound researches in anatomy (see i. 802), and in the knowledge and practice of medicine he appears to have been equally renowned. He professed himself a close adherent of Hippocrates, and adopted his theory of the humours. He also made extensive use of drugs and of bleeding. The reputation of Herophilus is attested by the fact that four considerable physicians wrote works about him and his writings, and he is further spoken of with the highest respect by Galen and Celsus. By the general voice of the medical world of antiquity he was placed only second to Hippocrates.

Erasistratus (d. 280 B.C.) was the contemporary and rival of Herophilus. Little is known of his life, .except that he spent some time at the court of Seleucus Nicator at Antioch before coming to Alexandria, and that he cultivated anatomy late in life, after he had taken up his abode in the latter city. His numerous works are also almost entirely lost, fragments only being preserved by Galen and others. Erasistratus, instead of following Hippocrates as Herophilus did, depreciated him, and seems to have been rather aggressive and independent in his views. He appears to have leaned to mechanical explanations of the symptoms of disease, as was especially the case with inflammation, of which he gave the first rational, though necessarily inadequate, theory.

The two schools composed of the followers of Herophilus and Erasistratus respectively long divided between them the medical world of Alexandria. The names of many prominent members of both sects have been preserved, but it would be useless to repeat them. The Herophilists still reverenced the memory of Hippocrates, and wrote numerous commentaries on his works. They produced many eminent anatomists, but in the end seem to have become lost in theoretical subtleties, and to have maintained too high a standard of literary cultivation. The school of Erasistratus was less distinguished in anatomy than that of Herophilus, but paid more attention to the special symptoms of diseases, and employed a great variety of drugs. It was longer-lived than that of Herophilus, for it still numbered many adherents in the 2nd century after Christ, a century after the latter had become extinct.

The Erasistrateans paved the way for what was in some respects the most important school which Alexandria produced, that known as the empiric, which, though it recognized no master by name, may be considered to have been founded by Philinus of Cos (280 B.C.), a pupil of Herophilus; but Serapion, a great name in antiquity, and Glaucias of Tarentum, who traced the empirical doctrine back to the writings of Hippocrates, are also named among its founders. The most striking peculiarity of the empirics was that they rejected anatomy, regarding it as useless to inquire into the causes of things, and thus, as they contended, being the more minute in their observation of the actual phenomena of disease. They professed that their whole practice was based upon experience, to which word they gave a special meaning. Three sources, and three only, could experience draw from: observation, history (i.e. recorded observation), and judgment by analogy. These three bases of knowledge were known as the "tripod" of the empirics. It should not, however, be forgotten that the empirics'read and industriously commented on the works of Hippocrates. They were extremely successful in practical matters, especially in surgery and in the use of drugs, and a large part of the routine knowledge of diseases and remedies which became traditional in the times of the Roman empire is believed to have been derived from them. In the 2nd century the school became closely connected with the philosophical sect of the Sceptics, whose leader, Sextus (200 B.C.), was an empirical physician. It lived and flourished far beyond this time, when transplanted to Rome, not less than in its native Alexandria, and appears to be recognizable even up to the beginning of the middle ages.

If we look at the work of the Alexandrian schools in medicine as a whole, we must admit that the progress made was great and permanent. The greatest service rendered to medicine was undoubtedly the systematic study of anatomy. It is clear that the knowledge of function (physiology) did not by any means keep pace with the knowledge of structure, and this was probably the reason why the important sect of the empirics were able entirely to dispense with anatomical knowledge. The doctrines of Hippocrates, though lightly thought of by the Erasistrateans, still were no doubt very widely accepted, but the practice of the Hippocratic school had been greatly improved in almost every department - surgery and obstetrics being probably those in which the Alexandrian practitioners could compare most favourably with those of modern times. We have now to trace the fortunes of this body of medical doctrine and practice when transplanted to Rome, and ultimately to the whole Roman world.

## Roman Medicine

The Romans cannot be said to have at any time originated or possessed an independent school of medicine. They had from early times a very complicated system of superstitious medicine, or religion, related to disease and the cure of disease, borrowed, as is thought, from the Etruscans; and, though the saying of Pliny that the Roman people got on for six hundred years without doctors was doubtless an exaggeration, and not, literally speaking, exact, it must be accepted for the broad truth which it contains. When a medical profession appears, it is, so far as we are able to trace it, as an importation from Greece.

The first Greek physician whose name is preserved as having migrated to Rome was Archagathus, who came over from the Peloponnesus in 218 B.C.; but there were probably others before him. When Greece was made a Roman province, the number of such physicians who sought their fortunes in Rome must have been very large. The bitter words of M. Porcius Cato, who disliked them. as he did other representatives of Greek culture, are evidence of this. The most eminent of these earlier Greek physicians at Rome was Asclepiades, the friend of Cicero (born 124 B.C. at Prusa in Bithynia). He came to Rome as a young man, and soon became distinguished both for his medical skill and his oratorical power. He introduced a system which, so far as we know, was his own, though founded upon the Epicurean philosophical creed; on the practical side it conformed pretty closely to the Stoic rule of life, thus adapting itself to the leanings of the better stamp of Romans in the later times of the republic. According to Asclepiades all diseases depended upon alterations in the size, number, arrangement or movement of the "atoms," of which, according to the doctrine of Epicurus, the body consisted. These atoms were united into passages (iropot) through which the juices of the body were conveyed. This doctrine, of which the developments need not further be followed, was important chiefly in so far that it was perfectly distinct from, and opposed to, the humoral pathology of Hippocrates. In the treatment of disease Asclepiades attached most importance to diet, exercise, passive movements or frictions, and the external use of cold water - in short, to a modified athletic training. He rejected the vis medicatrix naturae, pointing out that nature in many cases not only did not help but marred the cure. His knowledge of disease and surgical skill were, as appears from the accounts given by Celsus and Caelius Aurelianus, very considerable. Asclepiades had many pupils who adhered more or less closely to his doctrines, but it was especially one of them, Themison, who gave permanence to the teachings of his master by framing out of them, with some modifications, a new system of medical doctrine, and founding on this basis a school which lasted for some centuries in successful rivalry with the Hippocratic tradition, which, as we have seen, was up to that time the prevailing influence in medicine.

This system was known as methodism, its adherents as the methodici or methodists. Its main principles were that it was useless to consider the causes of a disease, or even the organ affected by the disease, and that it was sufficient to know what was common to all diseases, viz. their common qualities (communitates, KocvorJr€s).  Of these there were three possible forms - (1) relaxation, (2) contraction of the minute passages or ropoc, and (3) a mixed state, partly lax, partly constricted. The signs of these morbid states were to be found in the general constitution of the body, especially in the excretions. Besides this it was important only to consider whether the disease was acute or chronic, whether it was increasing, declining or stationary. Treatment of disease was directed not to any special organ, nor to producing the crises and critical discharges of the Hippocratic school, but to correcting the morbid common condition or "community," relaxing the body if it was constricted, causing contraction if it was too lax, and in the "mixed state" acting according to the predominant condition. This simple rule of treatment was the system or "method" from which the school took its name.

The methodists agreed with the empirics in one point, in their contempt for anatomy; but, strictly speaking, they were dogmatists, though with a dogma different from that of the Hippocratic school. Besides Themison, its systematic founder, the school boasted many physicians eminent in their day, among whom Thessalus of Tralles, a halfeducated and boastful pretender, was one of the most popular. He reversed the Hippocratic maxim "art is long," promising his scholars to teach them the whole of medicine in six months, and had inscribed upon his tomb iaTpovLKc, 7 r, as being superior to all living and bygone physicians.

In the and century a much greater name appears among the methodists, that of Soranus of Ephesus, a physician mentioned with praise even by Tertullian and Augustine, who practised at Rome in the reigns of Trajan and Hadrian. Soranus is known by a work, still extant in the Greek original, on the diseases of women, and also by the Latin work of Caelius Aurelianus, three centuries later, on acute and chronic diseases, which is based upon, if not, as some think, an actual translation of, the chief work of Soranus, and which is the principal source of our knowledge of the methodic school. The work on diseases of women is the only complete work on that subject which has come down to us from antiquity, and shows remarkable fullness of practical knowledge in relation to its subject. It is notable that an important instrument of research, the speculum, which has been reinvented in modern times, was used by Soranus; and specimens of still earlier date, showing great mechanical perfection, have been found among the ruins of Pompeii. The work on acute and chronic diseases is also full of practical knowledge, but penetrated with the theories of the methodists.

The methodic school lasted certainly for some centuries, and influenced the revival of medical science in the middle ages, though overshadowed by the greater reputation of Galen. It was the first definite product of Greek medicine on Roman soil, but was destined to be followed by others, which kept up a more or less successful rivalry with it, and with the Hippocratic tradition.

The so-called pneumatic school was founded by Athenaeus, in the 1st century after Christ. According to its doctrines the normal as well as diseased actions of the body were to be referred to the operation of the pneuma or universal soul. This doctrine, crudely transferred from philosophical speculation, was intended to reconcile the humoral (or Hippocratic) and solidist (or methodic) schools; but the methodists seem to have claimed Athenaeus as one of themselves.

The conflicts of the opposing schools, and the obvious deficiencies of each, led many physicians to try and combine the valuable parts of each system, and to call themselves eclectics. Among these were found many of the most eminent physicians of Graeco-Roman times. It may be sufficient to name Rufus or Ephesus (2nd century A.D), and Archigenes (fl. A.D. 90), who is mentioned by Juvenal.

Although no system or important doctrine of medicine was originated by the Roman intellect, and though the practice of the profession was probably almost entirely in the hands of the Greeks, the most complete picture which we have of medical thought and activity in Roman times is due to a Latin pen, and to one who was, in all probability, not a physician. A. Cornelius Celsus, a Roman patrician, who lived probably in the ist century, appears to have studied medicine as a branch of general knowledge. Whether he was a practising physician or not has been a matter of controversy. The conclusion supported by most evidence seems to be that he practised on his friends and dependants, but not as a remunerative profession. His well-known work, De medicina, was one of a series of treatises intended to embrace all knowledge proper for a man of the world. It was not meant for the physicians, and was certainly little read by them, as Celsus is quoted by no medical writer, and when referred to by Pliny, is spoken of as an author not a physician. There is no doubt that his work is chiefly a compilation; and Daremberg, with other scholars, has traced a large number of passages of the Latin text to the Greek originals from which they were translated. In the description of surgical operations the vagueness of the language seems sometimes to show that the author had not performed such himself; but in other parts, and especially in his historical introduction, he speaks with more confidence; and everywhere he compares and criticizes with learning and judgment. The whole body of medical literature belonging to the Hippocratic and Alexandrian times is ably summarized, and a knowledge of the state of medical science up to and during the times of the author is thus conveyed to us which can be obtained from no other source. The work of Celsus is thus for us only second in importance to the Hippocratic writings and the works of Galen; but it is valuable rather as a part of the history of medicine than as the subject of that history. It forms no link in the general chain of medical tradition, for the simple reason that the influence of Celsus (putting aside a few scanty allusions in medieval times) commenced in the 15th century, when his works were first discovered in manuscript or committed to the press. Since then, however, he has been almost up to our own times the most popular and widely read of all medical classics, partly for the qualities already indicated, partly because he was one of the few of those classics accessible to readers of Latin, and partly also because of the purity and classical perfection of his language.

Of Pliny, another encyclopaedic writer, a few words must be said, though he was not a physician. In his Natural History  we find as complete a summary of the popular medicine of his time as Celsus gives of the scientific medicine. Pliny disliked doctors, and lost no opportunity of depreciating regular medicine; nevertheless he has left many quotations from, and many details about, medical authors which are of the highest value. He is useful to us for what he wrote about the history of medicine, not for what he contributed. Like Celsus, he had little influence on succeeding medical literature or practice.

We now come to the writer who, above all others, gathered up into himself the divergent and scattered threads of ancient medicine, and out of whom again the greater part of modern European medicine has flowed. Galen was a man furnished with all the anatomical, medical and philosophical knowledge of his time; he had studied all kinds of natural curiosities, and had stood in near relation to important political events; he possessed enormous industry, great practical sagacity and unbounded literary fluency. He had, in fact, every quality necessary for an encyclopaedic writer, or even for a literary and professional autocrat. He found the medical profession of his time split up into a number of sects, medical science confounded under a multitude of dogmatic systems, the social status and moral integrity of physicians degraded. He appears. to have made it his object to reform these evils, to reconcile scientific acquirements and practical skill, to bring back the unity of medicine as it had been understood by Hippocrates, and at the same time to raise the dignity of medical practitioners.

Galen was as devoted to anatomical and, so far as then understood, physiological research as to practical medicine. He worked enthusiastically at dissection, though, the liberty of the Alexandrian schools no longer existing, he could dissect only animals, not the human body. In his anatomical studies Galen had a twofold object - a philosophical, to show the wisdom of the Creator in making everything fit to serve its purpose; and a practical, to aid the diagnosis, or recognition, of disease. The first led him into a teleological system so minute and overstrained as to defeat its own end; the second was successfully attained by giving greater precision and certainty to medical and surgical practice in difficult cases. His general physiology was essentially founded upon the Hippocratic theory of the four elements, with which he combined the notion of spirit (pneuma) penetrating all parts, and mingled with the humours in different proportions. It was on this field that he most vehemently attacked the prevailing atomistic and materialistic views of the methodic school, and his conception of the pneuma became in some respects half metaphysical. His own researches in special branches of physiology were important, but do not strictly belong to our present subject.

The application of physiology to the explanation of diseases, and thus to practice, was chiefly by the theory of the temperaments or mixtures which Galen founded upon the Hippocratic doctrine of humours, but developed with marvellous and fatal ingenuity. The normal condition or temperament of the body depended upon a proper mixture or proportion of the four elements - hot, cold, wet and dry. From faulty proportions of the same arose the intemperies (" distempers"), which, though not diseases, were the occasions of disease. Equal importance attached to faulty mixtures or dyscrasiae of the blood. By a combination of these morbid predispositions with the action of deleterious influences from without all diseases were produced. Galen showed extreme ingenuity in explaining all symptoms and all diseases on his system. No phenomenon was without a name, no problem without a solution. And, though it was precisely in his fine-spun subtlety that he departed furthest from scientific method and practical utility, it was this very quality which seems in the end to have secured his popularity and established his pre-eminence in the medical world.

Galen's use of drugs was influenced largely by the same theories. In drugs were to be recognized the same elementary qualities - hot, cold, moist, dry, &c. - as in the human body; and, on the principle of curing by contraries, the use of one or other was indicated. The writings of Galen contain less of simple objective observations than those of several other ancient physicians, all being swept into the current of dogmatic exposition. But there is enough to show the thoroughness and extent of his practical knowledge. Unfortunately it was neither this nor his zeal for research that chiefly won him followers, but the completeness of his theoretical explanations, which fell in with the mental habits of succeeding centuries, and were such as have flattered the intellectual indolence of all ages. But the reputation of Galen grew slowly; he does not appear to have enjoyed any pre-eminence over other physicians of his time, to most of whom he was strongly opposed in opinion. In the next generation he began to be esteemed only as a philosopher; gradually his system was implicitly accepted, and it enjoyed a great though not exclusive predominance till the fall of Roman civilization. When the Arabs possessed themselves of the scattered remains of Greek culture, the works of Galen were more highly esteemed than any others except those of Aristotle. Through the Arabs the Galenical system found its way back again to western Europe. Even when Arabian medicine gave way before the direct teaching of the Greek authors rescued from neglect, the authority of Galen was increased instead of being diminished; and he assumed a position of autocracy in medical science which was only slowly undermined by the growth of modern science in the 17th and 18th centuries.

The history of medicine in Roman times is by no means the same thing as the history of the fate of the works of Galen. For some centuries the methodic school was popular at Rome, and produced one physician, Caelius Aurelianus, who must be pronounced, next to Celsus, the most considerable of the Latin medical writers. His date was in all probability the end of the 4th or the beginning of the 5th century. The works bearing his name are, as has been said, entirely based upon the Greek of Soranus, but are important both because their Greek originals are lost, and because they are evidence of the state of medical practice in his own time. The popularity of Caelius is evidenced by the fact that in the 6th century an abridgment of his larger work was recommended by Cassiodorus to the Benedictine monks for the study of medicine.

Before quitting this period the name of Aretaeus of Cappadocia must be mentioned. So little is known about him that even his date cannot be fixed more closely than as being between the second half of the 1st century and the beginning of the 3rd. His works have been much admired for the purity of the Greek style, and his accurate descriptions of disease; but, as he quotes no medical author, and is quoted by none before Alexander of Aphrodisias at the beginning of the 3rd century, it is clear that he belonged to no school and founded none, and thus his position in the chain of medical tradition is quite uncertain. Alexander of Aphrodisias, who lived and wrote at Athens in the time of Septimius Severus, is best known by his commentaries on Aristotle, but also wrote a treatise on fevers, still extant.

## Ancient Medicine after Galen

The Byzantine school of medicine, which closely corresponds to the Byzantine literary and historical schools, followed closely in Galen's footsteps, and its writers were chiefly compilers and encyclopaedists. The earliest is Oribasius (326-403), whose date and position are fixed by his being the friend and court physician of Julian the Apostate. He was a Greek of Pergamum, educated in Alexandria, and long resident in Byzantium. His great work Evvaywyai tar pucai, of which only about one-third has been preserved, was a medical encyclopaedia founded on extracts from Hippocrates, Galen, Dioscorides (fl. A.D. 50) and certain Greek writers who are otherwise very imperfectly known. The work is thus one of great historical value but of no originality. The next name which requires to be mentioned is that of Aetius (A.D. 550), a compiler who closely followed Oribasius, but with inferior powers, and whose work also has an historical but no original value. A higher rank among medical writers is assigned to Alexander of Tralles (525-605), whose doctrine was that of an eclectic. His practical and therapeutical rules are evidently the fruit of his own experience, though it would be difficult to attribute to him any decided advance in medical knowledge. But the most prominent figure in Byzantine medicine is that of Paul of Aegina (Paulus Aegineta), who lived probably in the early part of the 7th century. His skill, especially in surgery, must have been considerable, and his 'Ia. rpucci gives a very complete picture of the achievements of the Greeks i n this department. Another work, on obstetrics, now lost, was equally famous, and procured for him, among the Arabs, the name of "the Obstetrician." His reputation lasted through the middle ages, and was not less in the Arabian schools than in the West. In this respect Paulus is a most important influence in the development of medicine. His great work on surgery was early translated into Arabic, and became the foundation of the surgery of Abulcasis, which in turn (to anticipate) was one of the chief sources of surgical knowledge to Europe in the middle ages. The succeeding period of Byzantine history was so little favourable to science that no name worthy of note occurs again (though many medical works of this period are still extant) till the 13th century, when we meet with a group of writers: Demetrius Pepagomenus, Nicolaus Myrepsus and Johannes, called Actuarius, who flourished under the protection of the Palaeologi. The work of the last has some independent merit; but all are interesting as showing a fusion of Greek and Arabian medicine, the latter having begun to exercise even in the 11th century a reflex influence on the schools of Byzantium. Something was borrowed even from the school of Salerno, and thus the close of Byzantine medicine is brought into connexion with the dawn of science in modern Europe.

In the West the period after Galen affords little evidence of anything but a gradual though unvarying decline in Roman medicine. Caelius Aurelianus, already referred to as the follower of Soranus, must be mentioned as showing the persistence of the methodic school. An abridgment of one of his writings, with the title of Aurelius, became the most popular of all Latin medical works. As a writer he was worthy of a better period of medical literature. Little else was produced in these times but compilations, of the most meagre kind, chiefly of the nature of herbals, or domestic receiptbooks; among the authors of which it may be sufficient to name Serenus Sammonicus (3rd century), Gargilius Martialis (3rd century) and Marcellus Empiricus (5th century). Certain compilations still extant bear the falsely-assumed names of eminent writers, such as Pliny and Hippocrates. A writer with the (perhaps assumed) name of Apuleius Platonicus produced a herbal which held its ground till the 15th century at least, and was in the 9th translated into Anglo-Saxon. These poor compilations, together with Latin translations of certain works of Galen and Hippocrates, formed a medical literature, meagre and unprogressive indeed, but of which a great part survived through the middle ages till the discovery of printing and revival of learning. It is important to remember that this obscure stream of tradition flowed on, only partially affected by the influx of Arabian, or even the early revival of purer classical learning.

## Arabian Medicine

The rise of the Mahommedan Empire, which influenced Europe so deeply both politically and intellectually, made its mark also in the history of medicine. As in the parallel case of the Roman conquest of Greece, the superior culture of the conquered race asserted its supremacy over their Arab conquerors. After the Mahommedan conquests became consolidated, and learning began to flourish, schools of medicine, often connected with hospitals and schools of pharmacy, arose in all the chief seats of Moslem power. At Damascus Greek medicine was zealously cultivated with the aid of Jewish and Christian teachers. In Bagdad, under the rule of Harun el Rashid and his successors, a still more flourishing school arose, where numerous translations of Greek medical works were made. The names of Mesua, or Yalhya ibn Masawaih (d. A.D. 857-858), celebrated for his knowledge of drugs, and Honein ibn Ishaq el `Ibadi (d. 873) or Joannitius, the translator and commentator of Hippocrates and Galen, belong to this period. Certain writings of Joannitius, translated into Latin, were popular in the middle ages in Europe, and were printed in the 16th century. At the same time the Arabs became acquainted with Indian medicine, and Indian physicians lived at the court of Bagdad. The Islamite rulers in Spain were not long behind those of the East in encouraging learning and medical science, and developed culture to a still higher degree of perfection. In that country much was due to the Jews, who had already established schools in places which were afterwards the seats of Moslem dominion. From the 10th to the 13th century was the brilliant period of Arabian medicine in Spain.1 The classical period of Arabian medicine begins with Rhazes (Abu Bakr Muhammad ibn Zakariya el-Razi, A.D. 925-926), a native of Rai in the province of Dailam (Persia), who practised with distinction at Bagdad; he followed the doctrines of Galen, but learnt much from Hippocrates. He was the first of the Arabs to treat medicine in a comprehensive and encyclopaedic, manner, surpassing probably in voluminousness Galen himself, though but a small proportion of his works are extant. Rhazes is deservedly remembered as having first described small-pox and measles in an accurate manner. Hali, i.e. `Ali ibn el-'Abbas, a Persian, wrote a medical textbook, known as the "Royal Book," which was the standard authority among the Arabs up to the time of Avicenna (A.D. 980-1037) and was more than once translated into Latin and printed. Other 1 See Dozy, Cat. Cod. Or. Lug. Bat. ii. 296.

writers of this century need not be mentioned here; but the next, the 11th century, is given as the probable though uncertain date of a writer who had a great influence on European medicine, Mesua the younger of Damascus, whose personality is obscure, and of whose very existence some historians have doubted, thinking that the name was assumed by some medieval Latin writer. The work De simplicibus, which bears his name, was for centuries a standard authority on what would now be called materia medica, was printed in twenty-six editions in the 15th century and later, and was used in the formation of the first London pharmacopoeia, issued by the College of Physicians in the reign of James I. Either to the 10th or the 11th century must be referred the name of another Arabian physician who has also attained the position of a classic, Abu'l Qasiin or Abulcasis, of El-Zahra, near Cordova, in Spain. His great work, Altasrif, a medical encyclopaedia, is chiefly valued for its surgical portion (already mentioned), which was translated into Latin in the 16th century, and was for some centuries a standard if not the standard authority on surgery in Europe. Among his own countrymen the fame and position of Abulcasis were soon eclipsed by the greater name of Avicenna.

Avicenna has always been regarded as the chief representative of Arabian medicine. He wrote on philosophy also, and in both subjects acquired the highest reputation through the whole of eastern Islam. In Mahommedan Spain he was lees regarded, but in Europe his works even eclipsed and superseded those of Hippocrates and Galen. His style and expository power are highly praised, but the subject-matter shows little originality. The work by which he is chiefly known, the celebrated "canon," is an encyclopaedia of medical and surgical knowledge, founded upon Galen, Aristotle, the later Greek physicians, and the earlier Arabian writers, singularly complete and systematic, but is thought not to show the practical experience of its author. As in the case of Galen, the formal and encyclopaedic character of Avicenna's works was the chief cause of his popularity and ascendancy, though in modern times these very qualities in a scientific or medical writer would rather cause him to become more speedily antiquated.

In the long list of Arabian medical writers none can here be mentioned except the great names of the Hispano-Moorish school, a school both philosophically and medically antagonistic to that of Avicenna. Of these the earliest is Avenzoar or Abumeron, that is, Abu Merwan `Abd al-Malik Ibn Zuhr (beginning of 12th century), a member of a family which gave several distinguished members to the medical profession. His chief work, Al-Teysir (facilitatio), is thought to show more practical experience than the writings of Avicenna, and to be less based upon dialectical subtleties. It was translated into Latin, and more than once printed, as were some of his lesser works, which thus formed a part of the contribution made by the Arabians to European medicine. His friend and pupil AvERROES of Cordova (q.v.), so well known for his philosophical writings, was also an author in medical subjects, and as such widely read in Latin. The famous Rabbi Maimonides (A.D. 1135-1201) (q.v.) closes for us the roll of medical writers of the Arabian school. His works exist chiefly in the original Arabic or in Hebrew translations; only some smaller treatises have been translated into Latin, so that no definite opinion can be formed as to their medical value. But, so far as is known, the independent and rationalistic spirit which the two last-named writers showed in philosophy did not lead them to take any original point of view in medicine.

The works of the Arabian medical writers who have now been mentioned form a very small fraction of the existing literature. Three hundred medical writers in Arabic are enumerated by Ferdinand Wiistenfeld (1808-1899), and other historians have enlarged the list (Haser), but only three have been printed in the original; a certain number more are known through old Latin translations, and the great majority still exist in manuscript. It is thus evident that the circumstance of having been translated (which may have been in some cases almost an accident) is what has chiefly determined the influence of particular writers on Western medicine. But it is improbable that further research will alter the general estimate of the value of Arabian medicine. There can be no doubt that it was in the main Greek medicine, modified to suit other climates, habits and national tastes, and with some important additions from Oriental sources. The greater part is taken from Hippocrates, Galen, Dioscorides and later Greek writers. The Latin medical writers were necessarily unknown to the Arabs; and this was partly the cause that even in Europe Galenic medicine assumed such a preponderance, the methodic school and Celsus being forgotten or neglected. In anatomy and physiology the Arabians distinctly went back; in surgery they showed no advance upon the Greeks; in practical medicine nothing new can be traced, except the description of certain diseases (e.g. small-pox and measles) unknown or imperfectly known to the Greeks; the only real advance was in pharmacy and the therapeutical use of drugs. By their relations with the farther East, the Arabs became acquainted with valuable new remedies which have held their ground till modern times; and their skill in chemistry enabled them to prepare new chemical remedies, and form many combinations of those already in use. They produced the first pharmacopoeia, and established the first apothecaries' shops. Many of the names and many forms of medi cines now used, and in fact the general outline of modern pharmacy, except so far as modified by modern chemistry, started with the Arabs. Thus does Arabian medicine appear as judged from a modern standpoint; but to medieval Europe, when little but a tradition remained of the great ancient schools, it was invested with a far higher degree of originality and importance.

It is now necessary to consider what was the state of medicine in Europe after the fall of the Western Empire and before the influence of Arabian science and literature began to be felt. This we may call the pre-Arabian or Salernitan period.

## Medicine in the Early Middle Ages: School of Salerno

In  medical as in civil history there is no real break. A continuous thread of learning and practice must have connected the last period of Roman medicine already mentioned with the dawn of science in the middle ages. But the intellectual thread is naturally traced with greater difficulty than that which is the theme of civil history; and in periods such as that from the 5th to the 10th century in Europe it is almost lost. The chief homes of medical as of other learning in these disturbed times were the monasteries. Though the science was certainly not advanced by their labours, it was saved from total oblivion, and many ancient medical works were preserved either in Latin or vernacular versions. The Anglo-Saxon Leechdoms 1 of the 11th century, published in the Rolls series of medieval chronicles and memorials, admirably illustrate the mixture of magic and superstition with the relics of ancient science which constituted monastic medicine. Similar works, in Latin or other languages, exist in manuscript in all the great European libraries. It was among the Benedictines that the monastic study of medicine first received a new direction, and aimed at a higher standard. The study of Hippocrates, Galen, and other classics was recommended by Cassiodorus (6th century), and in the original mother-abbey of Monte Cassino medicine was studied; but there was not there what could be called a medical school; nor had this foundation any connexion (as has been supposed) with the famous school of Salerno.

The origin of this, the most important source of medical knowledge in Europe in the early middle ages, is involved in obscurity. It is known that Salerno, a Roman colony, in a situation noted in ancient times for its salubrity, was in the 6th century at least the seat of a bishopric, and at the end of the 7th century of a Benedictine monastery, and that some of the prelates and higher clergy were distinguished for learning, and even for medical acquirements. But it has by recent researches been clearly established that the celebrated Schola salernitana was a purely secular institution. All that can with certainty be said is that a school or collection of schools gradually grew up in which especially medicine, but also, in a subordinate degree, law and philosophy were taught. In the 9th century Salernitan physicians were already spoken of, and the city was known as Civitas hippocratica. A little later we find great and royal personages resorting to Salerno for the restoration of their health, among whom was William of Normandy, afterwards the Conqueror. The number of students of medicine must at one time have been considerable, and in a corresponding degree the number of teachers. Among the latter many were married, and their wives and daughters appear also in the lists of professors. The most noted female professor was the celebrated Trotula in the 11th century. The Jewish element appears to have' been important among the students, and possibly among the professors. The reputation of the school was great till the 12th or 13th century, when the introduction of the Arab medicine was gradually fatal to it. The foundation of the university of Naples, and the rise of Montpellier, also contributed to its decline.

The teachings of the Salernitan doctors are pretty well known. through existing works, some of which have only recently been discovered and published. The best-known is the rhyming Latin poem on health by Joannes de Meditano, Regimen sanitatis Salerni, professedly written for the use of the "king of England," supposed to mean William the Conqueror; it had an immense reputation in the middle ages, and was afterwards many times printed, and translated into most European languages. This was a popular work intended for the laity; but there are others strictly professional.

1 Derived from the Anglo-Saxon laece, a physician, and dom, a law.

Among the writers it may be sufficient to mention here Gariopontus; Copho, who wrote the Anatome porci, a well-known medieval book; Joannes Platearius, first of a family of physicians bearing the same name, whose Practica, or medical compendium, was afterwards several times printed; and Trotula, believed to be the wife of the last-named. All of these fall into the first period before the advent of Arabian medicine. In the transitional period, when the Arabian school began to influence European medicine, but before the Salernitans were superseded, comes Nicolaus Praepositus, who wrote the Antidotarium, a collection of formulae for compound medicines, which became the standard work on the subject, and the foundation of many later compilations. An equally popular writer was Gilles de Corbeil (Aegidius Corboliensis), at one time a teacher at Salerno, afterwards court physician to Philip Augustus of France, who composed several poems in Latin hexameters on medical subjects. Two of them, on the urine and the pulse respectively, attained the position of medical classics.

None of these Salernitan works rise much above the rank of compilations, being founded on Hippocrates, Galen and later Greek writers, with an unmistakable mixture of the doctrines of the methodists. But they often show much practical experience, and exhibit the naturalistic method of the Hippocratic school. The general plan of treatment is dietetic rather than pharmaceutical, though the art of preparing drugs had reached a high degree of complexity at Salerno. Anatomy was as little regarded as it was in the later ancient schools, the empiric and methodic, but demonstrations of the parts of the body were given on swine. Although it cannot be said that the science of medicine was advanced at Salerno, still its decline was arrested at a time when every other branch of learning was rapidly falling into decay; and there can be no doubt that the observation of patients in hospitals, and probably clinical instruction, were made use of in learning and teaching. The school of Salerno thus forms a bridge between the ancient and the modern medicine, more direct though less conspicuous than that circuitous route, through Byzantium, Bagdad and Cordova, by which Hippocrates and Galen, in Arabian dress, again entered the European world. Though the glory of Salerno had departed, the school actually existed till it was finally dissolved by an edict of the emperor Napoleon I. in the year 1811.

## Introduction of Arabian Medicine: The Scholastic Period

About the middle of the 11th century the Arabian medical writers began to be known by Latin translations in the Western world. Constantinus Africanus, a monk, was the author of the earliest of such versions (A.D. roso); his labours were directed chiefly to the less important and less bulky Arabian authors, of whom Haly was the most noted; the real classics were not introduced till later. For some time the Salernitan medicine held its ground, and it was not till the conquest of Toledo by Alphonso of Castile that any large number of Western scholars came in contact with the learning of the Spanish Moors, and systematic efforts were made to translate their philosophical and medical works. Jewish scholars, often under the patronage of Christian bishops, were especially active in the work. In Sicily also the Oriental tendencies of Frederick Barbarossa and Frederick II. worked in the same direction. Gerard of Cremona, a physician of Toledo (1114-1187), made translations, it is said by command of Barbarossa, from Avicenna and others. It is needless to point out the influence of the crusades in making Eastern ideas known in the Western world. The influence of Arabian medicine soon began to be felt even in the Hippocratic city of Salerno, and in the r3th century is said to have held an even balance with the older medicine. After this time the foreign influence predominated; and by the time that the Aristotelian dialectic, in the introduction of which the Arabs had so large a share, prevailed in the schools of Europe, the Arabian version of Greek medicine reigned supreme in the medical world. That this movement coincided with the establishment of some of the older European universities is well known. The history of medicine in the period now opening is closely combined with the history of scholastic philosophy. Both were infected with the same dialectical subtlety, which was, from the nature of the subject, especially injurious to medicine.

At the same time, through the rise of the universities, medical learning was much more widely diffused, and the first definite forward movement was seen in the school of Montpellier, where a medical faculty existed early in the 12th century, afterwards united with faculties of law and philosophy. The medical school owed its foundation largely to Jewish teachers, themselves educated in the Moorish schools of Spain, and imbued with the intellectual independence of the Averroists. Its rising prosperity coincided with the decline of the school of Salerno. Montpellier became distinguished for the practical and empirical spirit of its medicine, as contrasted with the dogmatic and scholastic teaching of Paris and other universities. In Italy, Bologna and Padua were earliest distinguished for medical studies - the former preserving more of the Galenical tradition, the latter being more progressive and Averroist. The northern universities contributed little - the reputation even of Paris being of later growth.

The supremacy of Arabian medicine lasted till the revival of learning, when the study of the medical classics in their original language worked another revolution. The medical writers of this period, who chiefly drew from Arabian sources, have been called Arabists (though it is difficult to give any clear meaning to this term), and were afterwards known as the neoterics.

The medical literature of this period is extremely voluminous, but essentially second-hand, consisting mainly of commentaries on Hippocrates, Galen, Avicenna and others, or of compilations and compendia still less original than commentaries. Among these may be mentioned the Conciliator of Peter of Abano (1250-1315), the Aggregator of Jacob de Dondi (1298-1359), both of the school of Padua, and the Pandectae medicinae of the Salernitan Matthaeus Sylvaticus (d. 1342), a sort of medical glossary and dictionary. But for us the most interesting fact is the first appearance of Englishmen as authors of medical works having a European reputation, distinguished, according to the testimony of Haser, by a practical tendency characteristic - of the British race, and fostered in the school of Montpellier.

The first of these works is the Compendium medicinae, also called Laurea or Rosa anglicana, of Gilbert (Gilbertus Anglicus, about 1290), said to contain good observations on leprosy. A more important work, the Practica seu lilium medicinae, of Bernard Gordon, a Scottish professor at Montpellier (written in the year 1307), was more widely spread, being translated into French and Hebrew, and printed in several editions. Of these two physicians the first probably, the latter certainly, was educated and practised abroad, but John Gaddesden (1280?-1361), the author of Rosa anglica seu Practica medicinae (between 1305 and 1317), was a graduate in medicine of Merton College, Oxford, and court physician. His compendium is entirely wanting in originality, and perhaps unusually destitute of common sense, but it became so popular as to be reprinted up to the end of the 16th century. Works of this kind became still more abundant in the 14th and in the first half of the 15th century, till the wider distribution of the medical classics in the original put them out of fashion.

In surgery this period was far more productive than in medicine, especially in Italy and France, but the limits of our subject only permit us to mention Gulielmus de Saliceto of Piacenza (about 1275), Lanfranchi of Milan (died about 1306), the French surgeon, Guy de Chauliac (about 1350) and the Englishman, John Ardern (about 1350). In anatomy also the beginning of a new epoch was made by Mondino de Liucci or Mundinus (1275-1326), and his followers. The medical writings of Arnald de Villanova (c. 1235-1313) (if the Breviarium practicae be rightly ascribed to him) rise above the rank of compilations. Finally, in the 13th and especially the 14th century we find, under the name of consilia, the first medieval reports of medical cases which are preserved in such a form as to be intelligible. Collections of consilia were published, among others, by Gentilis Fulgineus before 1348, by Bartolomeo Montagnana (d. 1470), and by Baverius de Baveriis of Imola (about 1450). The last-named contains much that is interesting and readable.

## Period of the Revival of Learning

The impulse which all departments of intellectual activity received from the revival of Greek literature in Europe was felt by medicine among the rest. Not that the spirit of the science, or of its corresponding practice, was at once changed. The basis of medicine through the middle ages had been literary and dogmatic, and it was literary and dogmatic still; but the medical literature now brought to light - including as it did the more important works of Hippocrates and Galen, many of them hitherto unknown, and in addition the forgotten element of Latin medicine, especially the work of Celsus - was in itself far superior to the second-hand compilations and incorrect versions which had formerly been accepted as standards. The classical works, though still regarded with unreasoning reverence, were found to have a germinative and vivifying power that carried the mind out of the region of dogma, and prepared the way for the scientific movement which has been growing in strength up to our own day.

Two of the most important results of the revival of learning were indeed such as are excluded from the scope of this brief sketch - namely, the reawakening of anatomy, which to a large extent grew out of the study of the works of Galen, and the investigation of medicinal plants, to which a fresh impulse was given by the revival of Dioscorides (A.D. 50) and other ancient naturalists. The former brought with it necessarily a more accurate conception of physiology, and thus led up to the great discovery of Harvey, which was the turningpoint in modern medicine. The latter gave rise, on the one hand, to the modern science of botany, on the other to a more rational knowledge of drugs and their uses. At the same time, the discovery of America, and increased intercourse with the East, by introducing a variety of new plants, greatly accelerated the progress both of botany and pharmacology.

But it was not in these directions that improvement was first looked for. It was at first very naturally imagined that the simple revival of classical and especially of Greek literature would at once produce the same brilliant results in medicine as in literature and philosophy. The movement of reform started, of necessity, with scholars rather than practising physicians - more precisely with a group of learned men, whom we may be permitted, for the sake of a name, to call the medical humanists, equally enthusiastic in the cause of letters and of medicine. From both fields they hoped to expel the evils which were summed up in the word barbarism. Nearly all medieval medical literature was condemned under this name; and for it the humanists proposed to substitute the originals of Hippocrates and Galen, thus leading back medicine to its fountain-head. Since a knowledge of Greek was still confined to a small body of scholars, and a still smaller proportion of physicians, the first task was to translate the Greek classics into Latin. To this work several learned physicians, chiefly Italians, applied themselves with great ardour. Among the earliest were Nicolaus Leonicenus of Vicenza (1428-1524), Giovanni de Monte or Montanus (1498-1552), and many others in Italy. In northern Europe should be mentioned Gulielmus Copus (1471-1532) and Gunther of Andernach (1487-1584), better known as Guinterius Andernacensis, both for a time professors at Paris; and, among the greatest, Thomas Linacre (about 1460-1524; see Linacre). A little later Janus Cornarius or Hagenbut (150o-1558) and Leonhard Fuchs (1501-1566) in Germany, and John Kaye of Caius (1510-1572) in England, carried on the work. Symphorien Champier (Champerius or Campegius) of Lyons (1472-1539), a contemporary of Rabelais, and the patron of Servetus, wrote with fantastic enthusiasm on the superiority of the Greek to the Arabian physicians, and possibly did something to enlist in the same cause the two far greater men just mentioned. Rabelais not only lectured on Galen and Hippocrates, but edited some works of the latter; and Michael Servetus (1511-1553), in a little tract Syruporum universa ratio, defended the practice of Galen as compared with that of the Arabians. The great Aldine Press made an important contribution to the work, by editiones principes of Hippocrates and Galen in the original. Thus was the campaign opened against the medieval and Arabian writers, till finally Greek medicine assumed a predominant position, and Galen took the place of Avicenna. The result was recorded in a formal manner by the Florentine Academy, sometime shortly before 1 535: "Quae, excusso. Arabicae et barbarae servitutis medicae jugo, ex professo se Galenicam appellavit et profligato barbarorum exercitu unum totum et solum Galenum, ut optimum artis medicae authorem, in omnibus se sequuturam pollicita est." Janus Cornarius, from whom this is quoted, laments, however, that the Arabians still reigned in most of the schools of medicine, and that the Italian and French authors of works called Practica were still in high repute. The triumph of Galenism was therefore not complete by the middle of the 16th century. It was probably most so, and earliest, in the schools of Italy and in those of England, where the London College of Physicians might be regarded as an offshoot of the Italian schools. Paris was the stronghold of conservatism, and Germany was stirred by the teachings of one who must be considered apart from all schools - Paracelsus. The nature of the struggle between the rival systems may be well illustrated by a formidable controversy about the rules for bleeding in acute diseases. This operation, according to the Arabian practice, was always performed on a vein at a distance from the organ affected. The Hippocratic and also Galenic rule, to let blood from, or near to, the diseased organ, was revived by Pierre Brissot (1470-1522), a professor in the university of Paris. His attempt at reform, which was taken to be, as in effect it was, a revolt against the authority of the Arabian masters, led to his expulsion from Paris, and the formal prohibition by the parliament of his method. Upon this apparently trifling question arose a controversy which lasted many years, occupied several universities, and led to the interposition of personages no less important than the pope and the emperor, but which is thought to have largely contributed to the final downfall of the Arabian medicine.

Paracelsus and Chemical Medicine. - Contemporary with the school of medical humanists, but little influenced by them, lived in Germany a man of strange genius, of whose character and importance the most opposite opinions have been expressed. The first noticeable quality in Paracelsus (c. 1490-1541) is his revolutionary independence of thought, which was supported by his immense personal arrogance. Himself well trained in the learning and medical science of the day, he despised and trampled upon all traditional and authoritative teachings. He began his lectures at Basel by burning the books of Avicenna and others; he afterwards boasted of having read no books for ten years; he protested that his shoe-buckles were more learned than Galen and Avicenna. On the other hand, he spoke with respect of Hippocrates, and wrote a commentary on his Aphorisms. In this we see a spirit very different from the enthusiasm of the humanists for a purer and nobler philosophy than the scholastic and Arabian versions of Greek thought. There is no record of Paracelsus' knowledge of Greek, and as, at least in his student days, the most important works of Greek medicine were very imperfectly known, it is probable he had little first hand acquaintance with Galen or Hippocrates, while his breach with the humanists is the more conspicuous from his lecturing and writing chiefly in his native German.

Having thus made a clean sweep of nearly the whole of the dogmatic medicine, what did Paracelsus put in its place? Certainly not pure empiricism, or habits of objective observation. He had a dogma of his own - one founded, according to his German expositors, on the views of the Neoplatonists, of which a few disjointed specimens must here suffice. The human body was a "microcosm" which corresponded to the "macrocosm," and contained in itself all parts of visible nature, - sun, moon, stars and the poles of heaven. To know the nature of man and how to deal with it, the physician should study, not anatomy, which Paracelsus utterly rejected, but all parts of external nature. Life was a perpetual germinative process controlled by the indwelling spirit or Archeus; and diseases, according to the mystical conception of Paracelsus, were not natural but spiritual. Nature was sufficient for the cure of most diseases; art had only to interfere when the internal physician, the man himself, was tired or incapable. Then some remedy had to be introduced which should be antagonistic, not to the disease in a physical sense, but to the spiritual seed of the disease. These remedies were arcana - a word corresponding partly to what we now call specific remedies, but implying a mysterious connexion between the remedy and the "essence" of the disease. Arcana were often shown to be such by their physical properties, not only by such as heat, cold, &c., but by fortuitous resemblances to certain parts of the body; thus arose the famous doctrine of "signatures," or signs indicating the virtues and uses of natural objects, which was afterwards developed into great complexity. Great importance was also attached to chemically prepared remedies as containing the essence or spiritual quality of the material from which they were derived. The actual therapeutical resources of Paracelsus included a large number of metallic preparations, in the introduction of some of which he did good service, and, among vegetable preparations, the tincture of opium, still known by the name he gave it, laudanum. In this doubtless he derived much advantage from his knowledge of chemistry, though the science was as yet not disentangled from the secret traditions of alchemy, and was often mixed up with imposture.

German historians of medicine attach great importance to the revolt of Paracelsus against the prevailing systems, and trace in his writings anticipations of many scientific truths of later times. That his personality was influential, and his intrepid originality of great value as an example in his own country, is undeniable. As a national reformer he has been not inaptly compared to Luther. But his importance in the universal history of medicine we cannot estimate so highly. The chief immediate result we can trace is the introduction of certain mineral remedies, especially antimony, the use of which became a kind of badge of the disciples of Paracelsus. The use of these remedies was not, however, necessarily connected with a belief in his system, which seems to have spread little beyond his own country. Of the followers of Paracelsus some became mere mystical quacks and impostors. Others, of more learning and better repute, were distinguished from the regular physicians chiefly by their use of chemical remedies. In France the introduction of antimony gave rise to a bitter controversy which lasted into the 17th century, and led to the expulsion of some men of mark from the Paris faculty. In England "chemical medicine" is first heard of in the reign of Elizabeth, and was in like manner contemned and assailed by the College of Physicians and the Society of Apothecaries. But it should be remembered that all the chemical physicians did not call Paracelsus master. The most notorious of that school in England, Francis Anthony (1550-1623), never quotes Paracelsus, but relies upon Arnald de Villanova and Raimon Lull. From this time, however, it is always possible to trace a school of chemical practitioners, who, though condemned by the orthodox Galenists, held their ground, till in the 17th century a successor of Paracelsus arose in the celebrated J. B. Van Helmont.

## Consequences of the Revival of Ancient Medicine

The revival of Galenic and Hippocratic medicine, though ultimately it conferred the greatest benefits on medical sciences, did not immediately produce any important or salutary reform in practical medicine. The standard of excellence in the ancient writers was indeed far above the level of the 16th century; but the fatal habit of taking at second hand what should have been acquired by direct observation retarded progress more than the possession of better models assisted it, so that the fundamental faults of medieval science remained uncorrected.

Nevertheless some progress has to be recorded, even if not due directly to the study of ancient medicine. In the first place the 15th and 16th centuries were notable for the outbreak of certain epidemic diseases, which were unknown to the old physicians. Of these the chief was the "sweating sickness" or "English sweat," especially prevalent in, though not confined to, the country whence it is named. Among many descriptions of this disease, that by John Kaye or Caius, already referred to, was one of the best, and of great importance as showing that the works of Galen did not comprise all that could be known in medicine. The spread of syphilis, a disease equally unknown to the ancients, and the failure of Galen's remedies to cure it, had a similar effect.

In another direction the foundations of modern medicine were being laid during the 16th century - namely, by the introduction of clinical instruction in hospitals. In this Italy, and especially the renowned school of Padua, took the first step, where Giovanni De Monte (Montanus), (1498-1552), already mentioned as a humanist, gave clinical lectures on the patients in the hospital of St Francis, which may still be read with interest. Pupils flocked to him from all European countries; Germans are especially mentioned; a Polish student reported and published some of his lectures; and the Englishman Kaye was a zealous disciple, who does not, however, seem to have done anything towards transplanting this method of instruction to his own country. Inspections of the dead, to ascertain the nature of the disease, were made, though not without difficulty, and thus the modern period of the science of morbid anatomy was ushered in.

## Medicine in the 17th Century

The medicine of the early 17th century presents no features to distinguish it from that of the preceding century. The practice and theory of medicine were mainly founded upon Hippocrates and Galen, with everincreasing additions from the chemical school. But the development of mathematical and physical science soon introduced a fundamental change in the habits of thought with respect to medical doctrine.

These discoveries not only weakened or destroyed the respect for authority in matters of science, but brought about a marked tendency to mechanical explanations of life and disease. When William Harvey by his discovery of the circulation furnished an explanation of many vital processes which was reconcilable with the ordinary laws of mechanics, the efforts of medical theorists were naturally directed to bringing all the departments of medicine under similar laws. It is often assumed that the writings and influence of Bacon did much towards introducing a more scientific method into medicine and physiology. But, without discussing the general philosophical position or historical importance of Bacon, it may safely be said that his direct influence can be little traced in medical writings of the first half of the r 7th century. Harvey, as is well known, spoke slightingly of the great chancellor, and it is not till the rapid development of physical science in England and Holland in the latter part of the century, that we find Baconian principles explicitly recognized.

The dominant factors in the r 7th-century medicine were the discovery of the circulation by William Harvey (published in 1628), the mechanical philosophy of Descartes and the contemporary progress of physics, the teaching of Van Helmont and the introduction of chemical explanations of morbid processes, and finally, combined of all these, and inspiring them, the rise of the spirit of inquiry and innovation, which may be called the scientific movement. Before speaking in detail of these, we may note that by other influences quite independent of theories, important additions were made to practical medicine. The method of clinical instruction in hospitals, commenced by the Italians, was introduced into Holland, where it was greatly developed, especially at Leiden, in the hands of Francis de la Bo gy, called Sylvius (1641-1672). It is noteworthy that concurrently with the rise of clinical study the works of Hippocrates were more and more valued, while Galen began to sink into the background.

At the same time the discovery of new diseases, unknown to the ancients, and the keener attention which the great epidemics of plague caused to be paid to those already known, led to more minute study of the natural history of disease. The most important disease hitherto undescribed was rickets, first made known by Arnold de Boot, a Frisian who practised in Ireland, in 1649, and afterwards more fully in the celebrated work of Francis Glisson (1597-1677) in 1651. The plague was carefully studied by Isbrand de Diemerbroek, in his De Peste (1646), and others. Nathaniel Hodges of London (1629-1688) in 1665 seems to have been the first who had the courage to make a post mortem inspection of a plague patient. Christopher Bennet (1617-1655) wrote an important work on consumption in 1654. During the same period Many new remedies were introduced, the most important being cinchona-bark, brought to Spain in the year 1640. The progress of pharmacy was shown by the publication of Dispensatories or Pharmacopoeiae such as that of the Royal College of Physicians of London in 1618. This, like the earlier German works of the same kind (on which it was partly founded), contains both the traditional (Galenical) and the modern or chemical remedies.

## Van Helmont

The medicine of the 17th century was especially distinguished by the rise of sytems; and we must first speak of an eccentric genius who endeavoured to construct a system for himself, as original and opposed to tradition as that of Paracelsus. J. B. Van Helmont (1578-1644) was a man of noble family in Brussels, who, after mastering all other branches of learning as then understood, devoted himself with enthusiasm to medicine and chemistry. By education and position a little out of the regular lines of the profession, he took up in medicine an independent attitude. Well acquainted with the doctrines of Galen, he rejected them as thoroughly as Paracelsus did, and borrowed from the latter some definite ideas as well as his revolutionary spirit. The archeus of Paracelsus appears again, but with still further complications - the whole body being controlled by the archeus influus, and the organ of the soul and its various parts by the archei insiti, which are subject to the central archeus. Many of the symptoms of diseases were caused by the passions and perturbations of the archeus, and medicines acted by modifying the ideas of the same archeus. These and other notions cannot be here stated at sufficient length to be intelligible. It is enough to say that on this fantastic basis Helmont constructed a medical system which had some practical merits, that his therapeutical methods were mild and in many respects happy, and that he did service by applying newer chemical methods to the preparation of drugs. He thus had some share, though a share not generally recognized, in the foundation of the iatro-chemical school, now to be spoken of. But his avowed followers formed a small and discredited sect, which, in England at least, can be clearly traced in the latter part of the century.

## Discovery of the Circulation of the Blood

The influence of Harvey's discovery began to be felt before the middle of the century. Its merits were recognized by Descartes, among the first, nine years after its publication. For the history of the discovery, and its consequences in anatomy and physiology, we must refer to the article Harvey. In respect of practical medicine, much less effect was at first noticeable. But this example, combined with the Cartesian principles, set many active and ingenious spirits to work to reconstruct the whole of medicine on a physiological or even a mechanical basis - to endeavour to form what we should now call physiological or scientific medicine. The result of this was not to eliminate dogma from medicine, though it weakened the authority of the old dogma. The movement led rather to the formation of schools or systems of thought, which under various names lasted on into the 18th century, while the belief in the utility or necessity of schools and systems lasted much longer. The most important of these were the so-called iatro-physical or mechanical and the iatro-chemical schools.

## Iatro-Physical School

The iatro-physical school of medicine grew out of physiological theories. Its founder is held to have been G. A. Borelli (1608-1679), whose treatise De motu animalium, published in 1680, is regarded as marking an epoch in physiology. The tendency of the school was to explain the actions and functions of the body on physical, and especially on mechanical, principles. The movements of bones and muscles were referred to the theory of levers; the process of digestion was regarded as essentially a process of trituration; nutrition and secretion were shown to be dependent upon the tension of the vessels, and so forth. The developments of this school belong rather to the history of physiology, where they appear, seen in the light of modern science, as excellent though premature endeavours in a scientific direction. But the influence of these theories on practical medicine was not great. The more judicious of the mechanical or physical school refrained, as a judicious modern physiologist does, from too immediate an application of their principles to daily practice. Mechanical theories were introduced into pathology, in explanation of the processes of fever and the like, but had little or no influence on therapeutics. The most important men in this school after Borelli were Nicolaus Stensen (Steno), (1638-1686), Giorgio Baglivi (1669-1707) and Lorenzo Bellini (1643-1704). An English physician, William Cole (1635-1716), is also usually ranked with them. One of the most elaborate developments of the system was that of Archibald Pitcairne (1652-1713), a Scottish physician who became professor at Leiden, to be spoken of hereafter.

## Iatro-Chemical School

The so-called iatro-chemical school stood in a much closer relation to practical medicine than the iatrophysical. The principle which mainly distinguished it was not merely the use of chemical medicines in addition to the traditional, or, as they were called in distinction, "Galenical" remedies, but a theory of pathology or causation of disease entirely different from the prevailing "humoral" pathology. Its chief aim was to reconcile the new views in physiology and chemistry with practical medicine. In some theoretical views, and in the use of certain remedies, the school owed something to Van Helmont and Paracelsus, but took in the main an independent position. The founder of the iatrochemical school was Sylvius (1614-1672), who belonged to a French family settled in Holland, and was for fourteen years professor of medicine at Leiden, where he attracted students from all quarters of Europe. He made a resolute attempt to reconstruct medicine on the two bases of the doctrine of the circulation of the blood and the new views of chemistry. Fermentation, which was supposed to take place in the stomach, played an important part in the vital processes. Chemical disturbances of these processes, called acridities, &c., were the cause of fevers and other diseases. Sometimes acid sometimes alkaline properties predominated in the juices and secretions of the body, and produced corresponding disturbances. In nervous diseases disturbances of the vital "spirits" were most important. Still in some parts of his system Sylvius shows an anxiety to base his pathology on anatomical changes. The remedies he employed were partly galenical, partly chemical. He was very moderate in the use of bleeding.

The doctrines of Sylvius became widely spread in Holland and Germany; less so in France and Italy. In England they were not generally accepted till adopted with some modifications by Thomas Willis the great anatomist (1621-1675), who is the chief English representative of the chemical school. Willis was as thorough-going a chemist as Sylvius. He regarded all bodies, organic and inorganic, as composed of the three elements - spirit, sulphur and salt, the first being only found abundantly in animal bodies. The "intestine movement of particles" in every body, or fermentation, was the explanation of many of the processes of life and disease. The sensible properties and physical alterations of animal fluids and solids depended upon different proportions, movements and combinations of these particles. The elaborate work Pharmaceutice rationalis  (1674), based on these materials, had much influence in its time, though it was soon forgotten. But some parts of Willis's works, such as his descriptions of nervous diseases, and his account (the earliest) of diabetes, are classical contributions to scientific medicine. In the application of chemistry to the examination of secretions Willis made some important steps. The chemical school met with violent opposition, partly from the adherents of the ancient medicine, partly from the iatro-mechanical school. Towards the end of the 17th century appeared an English medical reformer who sided with none of these schools, but may be said in some respects to have surpassed and dispensed with them.

Sydenham and Locke. - Thomas Sydenham (1624-1689) was educated at Oxford and at Montpellier. He was well acquainted with the works of the ancient physicians, and probably fairly so with chemistry. Of his knowledge of anatomy nothing definite can be said, as he seldom refers to it. His main avowed principle was to do without hypothesis, and study the actual diseases in an unbiassed manner. As his model in medical methods, Sydenham repeatedly and pointedly refers to Hippocrates, and he has not unfairly been called the English Hippocrates. He resembled his Greek master in the high value he set on the study of the "natural history of disease"; in the importance he attached to "epidemic constitution" - that is, to the influence of weather and other natural causes in modifying disease; and further in his conception of the healing power of nature in disease, a doctrine which he even expanded beyond the teaching of Hippocrates. According to Sydenham, a disease is nothing more than an effort of nature to restore the health of the patient by the elimination of the morbific matter. The extent to which his practice was influenced by this and other a priori conceptions prevents us from classing Sydenham as a pure empiric; but he had the rare merit of never permitting himself to be enslaved even by his own theories. Still less was his mind warped by either of the two great systems, the classical and the chemical, which then divided the medical world. Sydenham's influence on European medicine was very great. His principles were welcomed as a return to nature by those who were weary of theoretical disputes. He introduced a milder and better way of treating fevers - especially small-pox, and gave strong support to the use of specific medicines - especially Peruvian bark. He was an advocate of bleeding, and often carried it to excess. Another important point in Sydenham's doctrine is his clear recognition of many diseases as being what would be now called specific, and not due merely to an alteration in the primary qualities or humours of the older schools. From this springs his high appreciation of specific medicines.

One name should always be mentioned along with Sydenhamthat of his friend John Locke. The great sensational philosopher was a thoroughly trained physician, and practised privately. He shared and defended many of Sydenham's principles, and in the few medical observations he has left shows himself to be even more thorough-going than the "English Hippocrates." It is deeply to be regretted in the interests of medicine that he did not write more. It is, however, reasonable to suppose that his commanding intellect often makes itself felt in the words of Sydenham. One sentence of Locke's, in a letter to William Molyneux, sums up the practical side of Sydenham's teaching: "You cannot imagine how far a little observation carefully made by a man not tied up to the four humours [Galen], or sal, sulphur and mercury [Paracelsus], or to acid and alcali [Sylvius and Willis] which has of late prevailed, will carry a man in the curing of diseases though very stubborn and dangerous; and that with very little and common things, and almost no medicine at all." We thus see that, while the great anatomists, physicists and chemists - men of the type of Willis, Borelli and Boyle - were laying foundations which were later on built up into the fabric of scientific medicine, little good was done by the premature application of their half-understood principles to practice. The reform of practical medicine was effected by men who aimed at, and partly succeeded in, rejecting all hypothesis and returning to the unbiassed study of natural processes, as shown in health and disease.

Sydenham showed that these processes might be profitably studied and dealt with without explaining them; and, by turning men's minds away from explanations and fixing them on facts, he enriched medicine with a method more fruitful than any discoveries in detail. From this time forth the reign of canonical authority in medicine was at an end, though the dogmatic spirit long survived.

## The r8th Century

The medicine of the i 8th century is notable, like that of the latter part of the 17th, for the striving after complete theoretical systems. The influence of the iatro-physical school was by no means exhausted; and in England, especially through the indirect influence of Sir Isaac Newton's (1642-1727) great astronomical generalizations, it took on a mathematical aspect, and is sometimes known as iatro-mathematical. This phase is most clearly developed in Archibald Pitcairne (1652-1713), who, though a determined opponent of metaphysical explanations, and of the chemical doctrines, gave to his own rude mechanical explanations of life and disease almost the dogmatic completeness of a theological system. His countryman and pupil, George Cheyne (1671-1743), who lived some years at Bath, published a new theory of fevers on the mechanical system, which had a great reputation. Their English contemporaries and successors, John Freind, William Cole, and Richard Mead, leaned also to mechanical explanations, but with a distrust of systematic theoretical completeness, which was perhaps partly a national characteristic, partly the result of the teaching of Sydenham and Locke. Freind (1675-1728) in his Emmenologia gave a mechanical explanation of the phenomena of menstruation. He is also one of the most distinguished writers on the history of medicine. Cole (1635-1716) (see above) published mechanical hypotheses concerning the causation of fevers which closely agree with those of the Italian iatro-mechanical school. More distinguished in his own day than any of these was Mead (1673-1754), one of the most accomplished and socially successful physicians of modern times. Mead was the pupil of the equally popular and successful John Radcliffe (1650-1714), who had acquired from Sydenham a contempt for book-learning, and belonged to no school in medicine but the school of common sense. Radcliffe left, however, no work requiring mention in a history of medicine. Mead, a man of great learning and intellectual activity, was an ardent advocate of the mathematical doctrines. "It is very evident," he says, "that all other means of improving medicine have been found ineffectual, by the stand it was at for two thousand years, and that, since mathematicians have sot themselves to the study of it, men already begin to talk so intelligibly and comprehensibly, even about abstruse matters, that it is to be hoped that mathematical learning will be the distinguishing mark of a physician and a quack." His Mechanical Account of Poisons, in the first edition (1702), gave an explanation of the effects of poisons, as acting only on the blood. Afterwards he modified his hypothesis, and referred the disturbances produced to the "nervous liquor," which he supposed to be a quantity of the "universal elastic matter" diffused through the universe, by which Newton explained the phenomena of light - i.e. what was afterwards called the luminiferous ether. Mead's treatise on The Power of the Sun and Moon over Human Bodies (1704), equally inspired by Newton's discoveries, was a premature attempt to assign the influence of atmospheric pressure and other cosmical causes in producing disease. His works contain, however, many original experiments, and excellent practical observations. James Keill (1673-1719) applied Newtonian and mechanical principles to the explanation of bodily functions with still greater accuracy and completeness; but his researches have more importance for physiology than for practical medicine.

## Boerhaave

None of these men founded a school - a result due in part to their intellectual character, in part to the absence in England of medical schools equivalent in position and importance to the universities of the Continent. An important academical position was, on the other hand, one of the reasons why a physician not very different in his way of thinking from the English physicians of the age of Queen Anne was able to take a far more predominant position in the medical world. Hermann Boerhaave (1668-1738) was emphatically a great teacher. He was for many years .professor of medicine at Leiden, where he lectured five hours a day, and excelled in influence and reputation not only his greatest forerunners, Montanus of Padua and Sylvius of Leiden, but probably every subsequent teacher. The hospital of Leiden, though with only twelve beds available for teaching, became the centre of medical influence in Europe. Many of the leading English physicians of the 18th century studied there; Gerard Van Swieten (1700-1772), a pupil of Boerhaave, transplanted the latter's method of teaching to Vienna, and founded the noted Vienna school of medicine.

As the organizer, and almost the constructor, of the modern method of clinical instruction, the services of Boerhaave to the progress of medicine were immense, and can hardly be overrated. In his teaching, as in his practice, he avowedly followed the method of Hippocrates and Sydenham, both of whom he enthusiastically admired. In his medical doctrines he must be pronounced an eclectic, though taking his stand mainly on the iatro-mechanical school. The bestknown parts of Boerhaave's system are his doctrines of inflammation, obstruction and "plethora. ' By the last named especially he was long remembered. His object was to make all the anatomical and physiological acquisitions of his age, even microscopical anatomy, which he diligently studied, available for use in the practice of medicine. He thus differed from Sydenham, who took almost as little account of modern science as of ancient dogma. Boerhaave may be in some respects compared tO Galen, but again differed from him in that he always abstained from attempting to reduce his knowledge to a uniform and coherent system. Boerhaave attached great importance to the study of the medical classics, but rather treated them historically than quoted them as canonical authorities. It almost follows from the nature of the case that the great task of Boerhaave's life, a synthesis of ancient and modern medicine, and the work in which this is chiefly contained, his. celebrated Institutions, could not have any great permanent value. Nearly the same thing is true even of the Aphorisms, in which, following the example of Hippocrates, he endeavoured to sum up the results of his long experience.

## Hoffmann and Stahl

We have now to speak of two writers in whom the systematic tendency of the 18th century showed itself most completely.

Friedrich Hoffmann (1660-1742), like Boerhaave, owed his influence, and perhaps partly his intellectual characteristics, to his academical position. He was in 1693 appointed the first professor of medicine in the university of Halle, then just founded by the elector Frederick III. Here he became, as did his contemporary and rival Stahl, a popular and influential teacher, though their university had not the European importance of Leiden. Hoffmann's" system "was apparently intended to reconcile the opposing" spiritual "and" materialistic "views of nature, and is thought to have been much influenced by the philosophy of Leibnitz. His medical theories rest upon a complete theory of the universe. Life depended upon a universally diffused ether, which animals breathe in from the atmosphere, and which is contained in all parts of the body. It accumulates in the brain, and there generates the" nervous fluid "or pneuma - a theory closely resembling that of Mead on the" nervous liquor,"unless indeed Mead borrowed it from Hoffmann. On this system are explained all the phenomena of life and disease. Health depends on the maintenance of a proper" tone "in the body - some diseases being produced by excess of tone, or" spasm "; others by" atony,"or want of tone. But it is impossible here to follow its further developments. Independently of his system, which has long ceased to exert any influence, Hoffmann made some contributions to practical medicine; and his great knowledge of chemistry enabled him to investigate the subject of mineral waters. He was equally skilful in pharmacy, but lowered his position by the practice, which would be unpardonable in a modern physician, of trafficking in secret remedies.

George Ernest Stahl (1660-1734) was for more than twenty years professor of medicine at Halle, and thus a colleague of Hoffmann, whom he resembled in constructing a complete theoretical system, though their systems had little or nothing in common. Stahl's chief aim was to oppose materialism. For mechanical conceptions he substituted the theory of" animism "- attributing to the soul the functions of ordinary animal life in man, while the life of other creatures was left to mechanical laws. The symptoms of disease were explained as efforts of the soul to rid itself from morbid influences, the soul acting reasonably with respect to the end of self-preservation. The anima thus corresponds partly to the" nature "of Sydenham, while In other respects it resembles the archeus of Van Helmont. Animism in its completeness met with little acceptance during the lifetime of its author, but influenced some of the iatro-physical school. Stahl was the author of the theory of" phlogiston "in chemistry, which in its day had great importance.

## Haller and Morgagni

From the subtleties of rival systems it is a satisfaction to turn to two movements in the medicine of the 18th century which, though they did not extinguish the spirit of system-making, opened up paths of investigation by which the systems were ultimately superseded. These are physiology in the modern sense, as dating from Haller, and pathological anatomy, as dating from Morgagni.

Albrecht von Haller (1708-1777) was a man of even more encyclopaedic attainments than Boerhaave. He advanced chemistry, botany, anatomy, as well as physiology, and was incessantly occupied in endeavouring to apply his scientific studies to practical medicine, thus continuing the work of his great teacher Boerhaave. Besides all this he was probably more profoundly acquainted with the literature and bibliography of medicine than any one before or since. Haller occupied in the new university of Gottingen (founded 1737) a position corresponding to that of Boerhaave at Leiden, and in like manner influenced a very large circle of pupils, The appreciation of his work in physiology belongs to the history of that science; we are only concerned here with its influence on medicine. Haller's definition of irritability as a property of muscular tissue, and its distinction from sensibility as a property of nerves, struck at the root of the prevailing hypothesis respecting animal activity. It was no longer necessary to suppose that a halfconscious" anima "was directing every movement. Moreover, Haller's views did not rest on a priori speculation, but on numerous experiments. He was among the first to investigate the action of medicines on healthy persons. Unfortunately the lesson which his contemporaries learnt was not the importance of experiment, but only the need of contriving ether" systems "less open to objection; and thus the influence of Haller led directly to the theoretical subtleties of William Cullen and John Brown, and only indirectly and later on to the general anatomy of M. F. X. Bichat. The great name of Haller does not therefore occupy a very prominent place in the history of practical medicine.

The work of Giovanni Battista Morgagni (1682-1771) had and still preserves a permanent importance beyond that of all the contemporary theorists. In a series of letters, De sedibus et causis morborum per anatomen indagatis, published when he was in his eightieth year, he describes the appearances met with at the post mortem examination as well as the symptoms during life in a number of cases of various diseases. It was not the first work of the kind. The Swiss physician, Theophile Bonet (1620-1689) had published his Sepulcretum in 1679; and observations of post mortem appearances had been made by Montanus, P. Tulp, Raymond Vieussens, A.M. Valsalva, G. M. Lancisi, Haller and others. But never before was so large a collection of cases brought together, described with such accuracy, or illustrated with equal anatomical and medical knowledge. Morgagni's work at once made an epoch in the science. Morbid anatomy now became a recognized branch of medical research, and the movement was started which has lasted till our own day.

The contribution of Morgagni to medical science must be regarded as in some respects the counterpart of Sydenham's. The latter had, in neglecting anatomy, neglected the most solid basis for studying the natural history of disease; though perhaps it was less from choice than because his practice, as he was not attached to a hospital, gave him no opportunities. But it is on the combination of the two methods - that of Sydenham and of Morgagni - that modern medicine rests; and it is through these that it has been able to make steady progress in its own field, independently of the advance of physiology or other sciences.

The method of Morgagni found many imitators, both in his own country and in others. In England the first important name in this field is at the same time that of the first writer of a systematic work in any language on morbid anatomy, Matthew Baillie (1761-1823), a nephew of John and William Hunter, who published his treatise in 1795.

## Cullen and Brown

It remains to speak of two systematic writers on medicine in the 18th century, whose great reputation prevents them from being passed over, though their real contribution to the progress of medicine was not great - Cullen and Brown.

William Cullen (1710-1790) was a most eminent and popular professor of medicine at Edinburgh. The same academical influences as surrounded the Dutch and German founders of systems were doubtless partly concerned in leading him to form the plan of a comprehensive system of medicine. Cullen's system was largely based on the new physiological doctrine of irritability, but is especially noticeable for the importance attached to nervous action. Thus even gout was regarded as a" neurosis."These pathological principles of Cullen are contained in his First Lines of the Practice of Physic, an extremely popular book, often reprinted and translated. More importance is to be attached to his Nosology or Classification of Diseases. The attempt to classify diseases on a natural-history plan was not new, having been commenced by Sauvages and others, and is perhaps not a task of the highest importance. Cullen drew out a classification of great and needless complexity, the chief part of which is now forgotten, but several of his main divisions are still preserved.

It is difficult to form a clear estimate of the importance of the last systematizer of medicine - John Brown (1735-1788) - for, though in England he has been but little regarded, the wide though shortlived popularity of his system on the Continent shows that it must have contained some elements of brilliancy, if not originality. His theory of medicine professed to explain the processes of life and disease, and the methods of cure, upon one simple principle - that of the property of" excitability,"in virtue of which the" exciting powers,"defined as being (1) external forces and (2) the functions of the system itself, call forth the vital phenomena" sense, motion, mental function and passion."All exciting powers are stimulant, the apparent debilitating or sedative effect of some being due to a deficiency in the degree of stimulus; so that the final conclusion is that" the whole phenomena of life, health as well as disease, consist in stimulus and nothing else."Brown recognized some diseases as sthenic, others as asthenic, the latter requiring stimulating treatment, the former the reverse; but his practical conclusion was that 97% of all diseases required a" stimulating "treatment. In this he claimed to have made the most salutary reform because all physicians from Hippocrates had treated diseases by depletion and debilitating measures with the object of curing by elimination. It would be unprofitable to attempt a complete analysis of the Brunonian system; and it is difficult now to understand why it attracted so much attention in its day. To us at the present time it seems merely a dialectical construction, having its beginning and end in definitions: the words power, stimulus, &c., being used in such a way as not to correspond to any precise physical conceptions, still less to definite material objects or forces. One recommendation of the system was that it favoured a milder system of treatment than was at that time in vogue; Brown may be said to have been the first advocate of the modern stimulant or feeding treatment of fevers. He advocated the use of" animal soups "or beef-tea. Further, he had the discernment to see that certain symptoms - such as convulsions and delirium, which were then commonly held always to indicate inflammation - were often really signs of weakness.

The fortunes of Brown's system (called, from having been originally written in Latin, the Brunonian) form one of the strangest chapters in the history of medicine. In Scotland, Brown so far won the sympathy of the students that riotous conflicts took place between his partisans and opponents. In England his system took little root. In Italy, on the other hand, it received enthusiastic support, and, naturally, a corresponding degree of opposition. The most important adherent to Brown's system was J. Rasori (1763-1837), who taught it as professor at Pavia, but afterwards substituted his own system of contra-stimulus. The theoretical differences between this and the" stimulus "theory need not be expounded. The practical difference in the corresponding treatment was very great, as Rasori advocated a copious use of bleeding and of depressing remedies, such as antimony. Joseph Frank (1774-1841), a German professor at Pavia, afterwards of Vienna, the author of an encyclopaedic work on medicine now forgotten, embraced the Brunonian system, though he afterwards introduced some modifications, and transplanted it to Vienna. Many names are quoted as partisans or opponents of the Brunonian system in Italy, but scarcely one of them has any other claim to be remembered. In Germany the new system called forth, a little later, no less enthusiasm and controversial heat. C. Girtanner (1760-1800) first began to spread the new ideas (though giving them out as his own), but Weikard was the first avowed advocate of the system. RSschlaub (1768-1835) modified Brown's system into the theory of excitement (Erregungstheorie), which for a time was extremely popular in Germany. The enthusiasm of the younger Brunonians in Germany was as great as in Edinburgh or in Italy, and led to serious riots in the university of Gottingen. In America the system was enthusiastically adopted by a noted physician, Benjamin Rush (1745-1813), of Philadelphia, who was followed by a considerable school. France was not more influenced by the new school than England. In both countries the tendency towards positive science and progress by objective investigation was too marked for any theoretical system to have more than a passing influence. In France, however, the influence of Brown's theories is very clearly seen in the writings of Francois J. V. Broussais, who, though not rightly classed with the system-makers, since his conclusions were partly based upon anatomical investigation, resembled them in his attempt to unite theory and practice in one comprehensive synthesis. The explanation of the meteoric splendour of the Brunonian system in other countries seems to be as follows. In Italy the period of intellectual decadence had set in, and no serious scientific ardour remained to withstand the novelties of abstract theory. In Germany the case was somewhat different. Intellectual activity was not wanting, but the great achievements of the 18th century in philosophy and the moral sciences had fostered a love of abstract speculation; and some sort of cosmical or general system was thought indispensable in every department of special science. Hence another generation had to pass away before Germany found herself on the level, in scientific investigation, of France and England.

Before the theoretic tendency of the 18th century was quite exhausted, it displayed itself in a system which, though in some respects isolated in the history of medicine, stands nearest to that of Brown - that, namely, of Hahnemann (see Homoeopathy). S. C. F. Hahnemann (1753-1844) was in conception as revolutionary a reformer of medicine as Paracelsus. He professed to base medicine entirely on a knowledge of symptoms, regarding all investigation of the causes of symptoms as useless. While thus rejecting all the lessons of morbid anatomy and pathology, he put forward views respecting the causes of disease which hardly bear to be seriously stated. All chronic maladies result either from three diseasespsora (the itch), syphilis or sycosis (a skin disease), or else are maladies produced by medicines. Seven-eighths of all chronic diseases are produced by itch driven inwards.' (It is fair to say that these views were published in one of his later works.) In treatment of disease Hahnemann rejected entirely the notion of a vis medicatrix naturae, and was guided by his well-known principle 1 The itch (scabies) is really an affection produced by the presence in the skin of a species of mite (Acarus scabiei), and when this is destroyed or removed the disease is at an end.

" similaa similibus curantur,"which he explained as depending on the law that in order to get rid of a disease some remedy must be given which should substitute for the disease an action dynamically similar, but weaker. The original malady being thus got rid of, the vital force would easily be able to cope with and extinguish the slighter disturbance caused by the remedy. Something very similar was held by Brown, who taught that" indirect debility was to be cured by a lesser degree of the same stimulus as had caused the original disturbance. Generally, however, Hahnemann's views contradict those of Brown, though moving somewhat in the same plane. In order to select remedies which should fulfil the indication of producing symptoms like those of the disease, Hahnemann made many observations of the action of drugs on healthy persons. He did not originate this line of research, for it had been pursued, if not originated, by Haller, and cultivated systematically by Tommasini, an Italian "contra-stimulist"; but he carried it out with much elaboration. His results, nevertheless, were vitiated by being obtained in the interest of a theory, and by singular want of discrimination. In his second period he developed the theory of "potentiality" or dynamization - namely, that medicines gained in strength by being diluted, if the dilution was accompanied by shaking or pounding, which was supposed to "potentialize" or increase the potency of the medicine. On this principle Hahnemann ordered his original tinctures to be reduced in strength to onefiftieth; these first dilutions again to one-fiftieth; and so on, even till the thirtieth dilution, which he himself used by preference, and to which he ascribed the highest "potentiality." From a theoretical point of view Hahnemann's is one of the abstract systems, pretending to universality, which modern medicine neither accepts nor finds it worth while to controvert. In the treatment of disease his practical innovations came at a fortunate time, when the excesses of the depletory system had only partially been superseded by the equally injurious opposite extreme of Brown's stimulant treatment. Hahnemann's use of mild and often quite inert remedies contrasted favourably with both of these. Further, he did good by insisting upon simplicity in prescribing, when it was the custom to give a number of drugs, often heterogeneous and inconsistent, in the same prescription. But these indirect benefits were quite independent of the truth or falsity of his theoretical system.

## Positive Progress in the 18th Century

In looking back on the repeated attempts in the 18th century to construct a universal system of medicine, it is impossible not to regret the waste of brilliant gifts and profound acquirements which they involved. It was fortunate, however, that the accumulation of positive knowledge in medicine did not cease. While Germany and Scotland, as the chief homes of abstract speculation, gave birth to most of the theories, progress in objective science was most marked in other countries - in Italy first, and afterwards in England and France. We must retrace our steps a little to enumerate several distinguished names which, from the nature of the case, hardly admit of classification.

In Italy the tradition of the great anatomists and physiologists of the 17th century produced a series of accurate observers and practitioners. Among the first of these were Antonio Maria Valsalva (1666-1723), still better known as an anatomist; Giovanni Maria Lancisi (1654-1720), also an anatomist, the author of a classical work on the diseases of the heart and aneurisms; and Ippolito Francisco Albertini (1662-1738), whose researches on the same class of diseases were no less important.

In France, Jean Baptiste Senac (1693-1770) wrote also an important work on the affections of the heart. Sauvages, otherwise F. B. de Lacroix (1706-1767), gave, under the title Nosologia methodica, a natural-history classification of diseases; Jean Astruc (1684-1766) contributed to the knowledge of general diseases. But the state of medicine in that country till the end of the 18th century was unsatisfactory as compared with some other parts of Europe.

In England the brilliancy of the early part of the century in practical medicine was hardly maintained to the end, and presented, indeed, a certain contrast with the remarkable and unflagging progress of surgery in the same period. The roll of the College of Physicians does not furnish many distinguished names. Among these should be mentioned John Fothergill (1712-1780), who investigated the "putrid sore throat" now called diphtheria, and the form of neuralgia popularly known as tic douloureux. A physician of Plymouth, John Huxham (1694-1768), made researches on epidemic fevers, in the spirit of Sydenham and Hippocrates, which are of the highest importance. William Heberden (1710-1801), a London physician, called by Samuel Johnson ultimus Romanorum, " the last of our learned physicians," left a rich legacy of practical observations in the Commentaries published after his death. More important in their results than any of these works were the discoveries of Edward Jenner, respecting the prevention of small-pox by vaccination, in which he superseded the partially useful but dangerous practice of inoculation, which. had been introduced into England in 1721. The history of this discovery need not be told here, but it may be pointed out that, apart from its practical importance, it has had great influence on the scientific study of infectious diseases. The name of John Pringle (1707-1782) should also be mentioned as one of the first to study epidemics of fevers occurring in prisons and camps. His work, entitled Observations on the Diseases of an Army, was translated into many European languages and became the standard authority on the subject.

In Germany the only important school of practical medicine was that of Vienna, as revived by Gerard van Swieten (1700-1772), a pupil of Boerhaave, under the patronage of Maria Theresa. Van Swieten's commentaries on the aphorisms of Boerhaave are thought more valuable than the original text. Other eminent names of the same school are Anton de Hain (1704-1776), Anton Stdrek (1731-1803), Maximilian Stoll (1742-1788), and John Peter Frank (1745-1821), father of Joseph Frank, before mentioned as an adherent of the Brownian system, and like his son carried away for a time by the new doctrines. This, the old "Vienna School," was not distinguished for any notable discoveries, but for success in clinical teaching, and for its sound method of studying the actual facts of disease during life and after death, which largely contributed to the establishment of the "positive medicine" of the 19th century.

One novelty, however, of the first importance is due to a Vienna physician of the period, Leopold Auenbrugger (1722-1809), the inventor of the method of recognizing diseases of the chest by percussion. Auenbrugger's method was that of direct percussion with the tips of the fingers, not that which is now used, of mediate percussion with the intervention of a finger or plessimeter; but the results of his method were the same and its value nearly as great. Auenbrugger's great work, the Inventum novum, was published in 1761. The new practice was received at first with contempt and even ridicule, and afterwards by Stoll and Peter Frank with only grudging approval. It did not receive due recognition till 1808, when J. N. Corvisart translated the Inventum novum into French, and Auenbrugger's method rapidly attained a European reputation. Surpassed, but not eclipsed, by the still more important art of auscultation introduced by R. T. H. Laennec, it is hardly too much to say that this simple and purely mechanical invention has had more influence on the development of modern medicine than all the "systems" evolved by the most brilliant intellects of the 18th century.

## Rise of the Positive School in France

The reform of medicine in France must be dated from the great intellectual awakening caused by the Revolution, but more definitely starts with the researches in anatomy and physiology of Marie Francois Xavier Bichat (1771-1802). The importance in science of Bichat's classical works, especially of the Anatomie generale, cannot be estimated here; we can only point out their value as supplying a new basis for pathology or the science of disease. Among the most ardent of his followers was Francois Joseph Victor Broussais (1772-1838), whose theoretical views, partly founded on those of Brown and partly on the so-called vitalist school of Theophile Bordeu (1722-1776) and Paul Joseph Barthez (1734-1806), differed from these essentially in being avowedly based on anatomical observations. Broussais's chief aim was to find an anatomical basis for all diseases, but he is especially known for his attempt to explain all fevers as a consequence of irritation or inflammation of the intestinal canal (gastroenterite). A number of other maladies, especially general diseases and those commonly regarded as nervous, were attributed to the same cause. It would be impossible now to trace the steps which led to this wild and long since exploded theory. It led, among other consequences, to an enormous misuse of bleeding. Leeches were his favourite instruments, and so much so that he is said to have used ioo,000 in his own hospital wards during one year. He was equalled if not surpassed in this excess by his follower Jean Bouillaud (1796-1881), known for his important work on heart diseases. Broussais's system, to which he gave the name of "Medecine physiologique," did much indirect good, in fixing attention upon morbid changes in the organs, and thus led to the rise of the strongly opposed anatomical and pathological school of Corvisart, Laennec and Bayle.

Jean Nicolas Corvisart (1755-1821) has already been mentioned as the translator and introducer into France of Auenbrugger's work on percussion. He introduced some improvements in the method, but the only real advance was the introduction of mediate percussion by Pierre Adolphe Piorry (1794-1879) in 1828. The discovery had, however, yet to be completed by that of auscultation, or listening to sounds produced in the chest by breathing, the movements of the heart, &c. The combination of these methods constitutes what is now known as physical diagnosis. Rene Theophile Hyacinthe Laennec (1781-1826) was the inventor of this most important perhaps of all methods of medical research. Except for some trifling notices of sounds heard in certain diseases, this method was entirely new. It was definitely expounded in an almost complete form in his work De l'auscultation mediate, published in 1819. Laennec attached undue importance to the use of the stethoscope, and laid too much weight on specific signs of specific diseases; otherwise his method in its main features has remained unchanged. The result of his discovery was an entire revolution in the knowledge of diseases of the chest; but it would be a mistake to forget that an essential factor in this revolution was the simultaneous study of the condition of the diseased organs as seen after death. Without the latter, it is difficult to see how the information conveyed by sounds could ever have been verified. This increase of knowledge is therefore due, not to auscultation alone, but to auscultation combined with morbid anatomy. In the case of Laennec himself this qualification takes nothing from his fame, for he studied so minutely the relations of post-mortem appearances to symptoms during life that, had he not discovered auscultation, his researches in morbid anatomy would have made him famous. The pathologico-anatomical method was also followed with great zeal and success by Gaspard Laurent Bayle (1774-1816), whose researches on tubercle, and the changes of the lungs and other organs in consumption, are the foundation of most that has been done since his time. It was of course antecedent to the discovery of auscultation. Starting from these men arose a school of physicians who endeavoured to give to the study of symptoms the same precision as belonged to anatomical observations, and by the combination of both methods made a new era in clinical medicine. Among these were Auguste Francois Chomel (1788-1858), Pierre Charles Alexandre Louis (1787-1872), Jean Cruveilhier (1791-1874) and Gabriel Andral (1797-1876). Louis, by his researches on pulmonary consumption and typhoid fever, had the chief merit of refuting the doctrines of Broussais. In another respect also he aided in establishing an exact science of medicine by the introduction of the numerical or statistical method. By this method only can the fallacies which are attendant on drawing conclusions from isolated cases be avoided; and thus the chief objection which has been made to regarding medicine as an inductive science has been removed. Louis's method was improved and systematized by Louis Denis Jules Gavarret (1809-1890) and its utility is now universally recognized. During this brilliant period of French medicine the superiority of the school of Paris could hardly be contested. We can only mention the names of Pierre Bretonneau (1771-1862), Louis Leon Rostan (1790-1866), Jean Louis D'Alibert (1766-1837), Pierre Francois Olive Rayer (1793-1867) and Armand Trousseau (1801-1866), the eloquent and popular teacher.

English Medicine from 1800 to 1840\. - The progress of medicine in England during this period displays the same characteristics as at other times, viz. a gradual and uninterrupted development, without startling changes such as are caused by the sudden rise or fall of a new school. Hardly any theoretical system is of English birth; Erasmus Darwin (1731-1802), the grandfather of the great Charles Darwin, alone makes an exception. In his Zoonomia (1794) he expounded a theory of life and disease which had some resemblance to that of Brown, though arrived at (he says) by a different chain of reasoning.

Darwin's work shows, however, the tendency to connect medicine with physical science, which was an immediate consequence of the scientific discoveries of the end of the 18th century, when Priestley and Cavendish in England exercised the same influence as Lavoisier in France. The English school of medicine was also profoundly stirred by the teachings of the two brothers William and John Hunter, especially the latter - who must therefore be briefly mentioned, though their own researches were chiefly concerned with subjects lying a little outside the limits of this sketch. William Hunter (1718-1783) was known in London as a brilliant teacher of anatomy and successful obstetric physician; his younger brother and pupil, John Hunter (1728-1793), was also a teacher of anatomy, and practised as a surgeon. His immense contributions to anatomy and pathology cannot be estimated here, but his services in stimulating research and training investigators belong to the history of general medicine. They are sufficiently evidenced by the fact that Edward Jenner and Matthew Baillie were his pupils.

The same scientific bent is seen in the greater attention paid to morbid anatomy (which dates from Baillie) and the more scientific method of studying diseases. An instance of the latter is the work of Robert Willan (1757-1812) on diseases of the skin - a department of medicine in which abstract and hypothetical views had been especially injurious. Willan, by following the natural-history method of Sydenham, at once put the study on a sound basis; and his work has been the starting-point of the most important modern researches. About the same time William Charles Wells (1757-1817), a scientific investigator of remarkable power, and the author of a celebrated essay on dew, published observations on alterations in the urine, which, though little noticed at the time, were of great value as assisting in the important discovery made some years afterwards by Richard Bright.

These observers, and others who cannot be mentioned here, belong to the period when English medicine was still little influenced by the French school. Shortly after 1815, however, when the continent of Europe was again open to English travellers, many English doctors studied in Paris, and the discoveries of their great French contemporaries began to be known. The method of auscultation was soon introduced into England by pupils of Laennec. John Forbes (1787-1861) in 1824, and William Stokes (1804-1878) of Dublin in 1825, published treatises on the use of the stethoscope. Forbes also translated the works of Laennec and Auenbrugger, and an entire revolution was soon effected in the knowledge of diseases of the chest. James Hope (1801-1841) and Peter Mere Latham (1789-1875) further developed this subject, and the former was also known for his researches in morbid anatomy. The combination of clinical and anatomical research led, as in the hands of the great French physicians, to important discoveries by English investigators. The discovery by Richard Bright (1789-1858) of the disease of the kidneys known by his name proved to be one of the most momentous of the century. It was published in Reports of Medical Cases 1827-1831.. Thomas Addison (1793-1860) takes, somewhat later, a scarcely inferior place. The remarkable physiological discoveries of Sir Charles Bell (1774-1842) and Marshall Hall (1790-1857) for the first time rendered possible the discrimination of diseases of the spinal cord. Several of these physicians were also eminent for their clinical teaching - an art in which Englishmen had up till then been greatly deficient.

Although many names of scarcely less note might be mentioned among the London physicians of the early part of the century, we must pass them over to consider the progress of medicine in Scotland and Ireland. In Edinburgh the admirable teaching of Cullen had raised the medical faculty to a height of prosperity of which his successor, James Gregory (1758-1821), was not unworthy. His nephew, William Pulteney Alison (1790-1859), was even more widely known. These great teachers maintained in the northern university a continuous tradition of successful teaching, which the difference in academical and other circumstances rendered hardly possible in London. Nor was the northern school wanting in special investigators, such as John Abercrombie (1780-1844), known for his work on diseases of the brain and spinal cord, published in 1828, and many others. Turning to Ireland, it should be said that the Dublin school in this period produced two physicians of the highest distinction. Robert James Graves (1796-1853) was a most eminent clinical teacher and observer, whose lectures are regarded as the model of clinical teaching, and indeed served as such to the most popular teacher of the Paris school in the middle of this century, Trousseau. William Stokes (1804-1878) was especially known for his works on diseases of the chest and of the heart, and for his clinical teaching.

## German Medicine from 1800 to 1840

Of the other countries of Europe, it is now only necessary to mention Germany. Here the chief home of positive medicine was still for a long time Vienna, where the "new Vienna school" continued and surpassed the glory of the old. Joseph Skoda (1805-1881) extended, and in some respects corrected, the art of auscultation as left by Laennec. Karl Rokitansky (1804-1878), by his colossal labours, placed the science of morbid anatomy on a permanent basis, and enriched it by numerous discoveries of detail. Most of the ardent cultivators of this science in Germany in the next generation were his pupils. In the other German schools, though some great names might be found, as Moritz Heinrich Romberg (1795-1873), the founder of the modern era in the study of nervous diseases, the general spirit was scholastic and the result barren till the teaching of one man, whom the modern German physicians generally regard as the regenerator of scientific medicine in their country, made itself felt. Johann Lucas Schdnlein (1793-1864) was first professor at Wiirzburg, afterwards at Zurich, and for twenty years at Berlin (from 1839-1859). Schdnlein's positive contributions to medical science were not large; but he made in 1839 one discovery, apparently small, but in reality most suggestive, namely, that the contagious disease of the head called favus is produced by the growth in the hair of a parasitic fungus. In this may be found the germ of the startling modern discoveries in parasitic diseases. His systematic doctrines founded the so-called "natural history school"; but his real merit was that of the founder or introducer of a method. In the words of H. Haser: "Schdnlein has the incontestable merit of having been the first to establish in Germany the exact method of the French and the English, and to impregnate this method with the vivifying spirit of German research." (J. F. P.) Modern Progress. - In recent times the positive bent of modern knowledge and methods in other spheres of science and thought, and especially in biology, has influenced medicine profoundly. Minuter accuracy of observation was inculcated by the labours and teaching of the great anatomists of the 17th century; and, for modern times, experimental physiology was instituted by Harvey, anatomy having done little to interpret life in its dynamic aspects. For medicine in England Harvey did what William Gilbert did for physics and Robert Boyle for chemistry: he insisted upon direct interrogation of natural processes, and thereby annihilated the ascendancy of mere authority, which, while nations were in the making, was an essential principle in the welding together of heterogeneous and turbulent peoples. The degradation of medicine between Galen and Harvey, if in part it consisted in the blind following of the authority of the former physician, was primarily due to other causes; and its new development was not due to the discovery of the experimental method alone: social and political causes also are concerned in the advance even of the exact sciences. Among such contributory causes is the more familiar intercourse of settled nations which we enjoy in our own day; the ideas of one nation rapidly permeate neighbouring nations, and by the means of printed books penetrate into remoter provinces and into distant lands. Hence the description of the advance of medicine in western Europe and America may for the latest stage be taken as a whole, without that separate treatment, nation by nation, which in the history of earlier times was necessary. Italy lost the leading place she had taken in the new development of science. The several influences of modern Germany, France and America became of the first importance to English medicine; but these tides, instead of pursuing their courses as independent streams, have become confluent. The work of Theodor Schwann (1810-1882), Johannes Muller (1809-1875), Rudolph Virchow and Karl Ludwig (1816-1895) in Germany, of R. T. H. Laennec and Claude Bernard in France, was accepted in England, as that of Matthew Baillie, Charles Bell, Bright, Graves and others of the British school, quickly made itself felt abroad.

The character of modern medicine cannot be summed in a word, as, with more or less aptness, that of some previous periods may be. Modern medicine, like modern ?xperiscience, is as boldly speculative as it has been in mental  any age, and yet it is as observant as in any naturalistic period; its success lies in the addition to these qualities of the method of verification; the fault of previous times being not the activity of the speculative faculty, without which no science can be fertile, but the lack of methodical reference of all and sundry propositions, and parts of propositions, to the test of experiment. In no department is the experimental method more continually justified than in that of the natural history of disease, which at first sight would seem to have a certain independence of it and a somewhat exclusive value of its own. Hippocrates had no opportunity of verification by necropsy, and Sydenham ignored pathology; yet the clinical features of many but recently described diseases, such, for example, as that named after Graves, and myxoedema, both associated with perversions of the thyroid gland, lay as open to the eye of physicians in the past as to our own. Again, to the naturalist the symptoms of tabes dorsalis were distinctive enough, had he noted them. No aid to the trained eye was necessary for such observations, and for many other such; yet, if we take Sir Thomas Watson (1792-1882) as a modern Sydenham, we may find in his lectures no suspicion that there may be a palsy of muscular co-ordination apart from deprivation of strength. Indeed, it does not seem to have occurred to any one to compare the muscular strength in the various kinds of paraplegia. Thus it was, partly because the habit of acceptance of authority, waning but far from extirpated, dictated to the clinical observer what he should see; partly because the eye of the clinical observer lacked that special training which the habit and influence of experimental verification alone can give, that physicians, even acute and practised physicians, failed to see many and many a symptomatic series which went through its evolutions conspicuously enough, and needed for its appreciation no unknown aids or methods of research, nor any further advances of pathology. We see now that the practice of the experimental method endows with a new vision both the experimenter himself and, through his influence, those who are associated with him in medical science, even if these be not themselves actually engaged in experiment; a new discipline is imposed upon old faculties, as is seen as well in other sciences as in those on which medicine more directly depends. And it is not only the perceptions of eye or ear which tell, but also the association of concepts behind these adits of the mind. It was the concepts derived from the experimental methods of Harvey, Lavoisier, Liebig, Claude Bernard, Helmholtz, Darwin, Pasteur, Lister and others which, directly or indirectly, trained the eyes of clinicians to observe more closely and accurately; and not of clinicians only, but also of pathologists, such as Matthew Baillie, Cruveilhier, Rokitansky, Bright, Virchowto name but a few of those who, with (as must be admitted) new facilities for necropsies, began to pile upon us discoveries in morbid anatomy and histology. If at first in the 18th century, and in the earlier 19th, the discoveries in this branch of medical knowledge had a certain isolation, due perhaps to the prepossessions of the school of Sydenham, they soon became the property of the physician, and were brought into co-ordination with the clinical phenomena of disease. The great Morgagni, the founder of morbid anatomy, himself set the example of carrying on this study parallel with clinical observation; and always insisted that the clinical story of the case should be brought side by side with the revelations of the necropsy. In pathology, indeed, Virchow's (1821-1902) influence in the transfiguration of this branch of science may almost be compared to that of Darwin and Pasteur in their respective domains. In the last quarter of the 19th century the conception grew clearer that morbid anatomy for the most part demonstrates disease in its static aspects only, and also for the most part in the particular aspect of final demolition; and it became manifest as pathology and clinical medicine became more and more thoroughly integrated, that the processes which initiate and are concerned in this dissolution were not revealed by the scalpel.

Again, the physician as naturalist, though stimulated by the pathologist to delineate disease in its fuller manifestations, yet was hampered in a measure by the didactic method of constructing "types" which should command the attention of the disciple and rivet themselves on his memory; thus too often those incipient and transitory phases which initiate the paths of dissolution were missed. Not only so, but the physician, thus fascinated by "types," and impressed by the silent monumentsof the pathological museum, was led to localize disease too much, to isolate the acts of nature, and to forget not only the continuity of the phases which lead up to the exemplary forms, or link them together, but to forget also that even between the types themselves relations of affinity must exist - and these oftentimes none the less intimate for apparent diversities of form, for types of widely different form may be, and indeed often are, more closely allied than types which have more superficial resemblance - and to forget, moreover, how largely negative is the process of abstraction by which types are imagined. Upon this too static a view, both of clinical type and of post-mortem-room pathology, came a despairing spirit, almost of fatalism, which in the contemplation of organic ruins lost the hope of cure of organic diseases. So prognosis became pessimistic, and the therapeutics of the abler men negative, until fresh hopes arose of stemming the tides of evil at their earliest flow. Such was medicine, statically ordered in pathology, statically ordered in its clinical concepts, when, on the 24th of November 1859 the Origin of Species was published. It is no exa eration to say that this epoch-making work gg }' p g brought to birth a world of conceptions as new as the work of Copernicus. For the natural philosopher the whole point of view of things was changed; in biology not only had the anthropocentric point of view been banished, but the ancient concept of perpetual flux was brought home to ordinary men, and entered for good into the framework of thought. The study of comparative pathology, yet in an inchoate stage, and of embryology, illuminated and enlarged biological conceptions, both normal and abnormal; and the ens reale subsistens in corpore  disappeared for ever - at any rate from physiology and medicine. Before Darwin - if the name of Darwin may be used to signify the transformation of thought of which he was the chief artificer - natural objects were regarded, not in medicine and pathology only, as a set of hidebound events; and natural operations as moving in fixed grooves, after a fashion which it is now difficult for us to realize. With the melting of the ice the more daring spirits dashed into the new current with such ardour that for them all traditions, all institutions, were thrown into hotchpot; even elderly and sober physicians took enough of the infection to liberate their minds, and, in the field of the several diseases and in that of post-mortem pathology, the hollowness of classification by superficial resemblance, the transitoriness of forms, and the flow of processes, broke upon the view. Thus it came about not only that classifications of disease based on superficial likeness - such as jaundice, dropsy, inflammation - were broken up, and their parts redistributed, but also that even more set diseases began to lose their settlements, and were recognized as terms of series, as transitory or culminating phases of perturbations which might be traced to their origins, and in their earlier stages perhaps withstood.

The doctrine of heredity in disease thus took a larger aspect; the view of morbid series was no longer bounded even by the life of the individual; and the propagation of taints, and of morbid varieties of man, from generation to generation proved to be no mere repetition of fixed features but, even more frequently, to be modes of development or of dissolution betraying themselves often in widely dissimilar forms, in series often extending over many lives, the terms of which at first sight had seemed wholly disparate. Thus, for example, as generations succeed one another, nervous disorders appear in various guise; epilepsy, megrim, insanity, asthma, hysteria, neurasthenia, a motley array at first sight, seemed to reveal themselves as terms of a morbid series; not only so, but certain disorders of other systems also might be members of the series, such as certain diseases of the skin, and even peculiar susceptibilities or immunities in respect of infections from without. On the other hand, not a few disorders proved to be alien to classes to which narrower views of causation had referred them; of such are tabes dorsalis, neuritis, infantile palsy or tetanus, now removed from the category of primary nervous diseases and placed in one or other of the class of infections; or, conversely, certain forms of disease of the joints are now regarded with some certainty as members of more than one series of diseases chiefly manifest in the nervous system. In the effects of simpler poisons the recognition of unity in diversity, as in the affiliation of a peripheral neuritis to arsenic, illustrated more definitely this serial or etiological method of classifying diseases. On the other hand, inheritance was dismissed, or survived only as a "susceptibility," in the cases of tubercle, leprosy and some other maladies now recognized as infectious; while in others, as in syphilis, it was seen to consist in a translation of the infectious element from parent to offspring. These new conceptions of the multiplicity in unity of disease, and of the fluidity and continuity of morbid processes, might have led to vagueness and over-boldness in speculation and reconstruction, had not the experimental method been at hand with clues and tests for the several series. Of this method the rise and wonderful extension of the science of bacteriology also furnished no inconsiderable part.

In the disease of the scalp called favus, Schonlein had discovered a minute mycelial fungus; a remarkable discovery, for it was the first conspicuous step in the attribution of diseases to the action of minute parasites. Schbnlein thus did something to introduce new and positive conceptions and exacter methods into Germany; but unfortunately his own mind retained the abstract habit of his country, and his abilities were dissipated in the mere speculations of Schelling. Similarly Karl Hoffmann of Wiirzburg wasted his appreciations of the newer schools of developmental biology in fanciful notions of human diseases as reversions to normal stages of lower animals; scrofula being for him a reversion to the insect, rickets to the mollusc, epilepsy to the oscillaria, and so forth. Even that distinguished physiologist Johannes Muller remained a staunch vitalist. Fortunately Germany, which at the beginning of the century was delivered over to Brownism and vitalism and was deaf to Bichat, was rescued from this sort of barrenness by the brilliant experimental work of Claude Bernard and Pasteur in France - work which, as regards the attenuated virus, was a development of that of Edward Jenner, and indeed of Schwann, Robert Koch worthily following Pasteur with his work on the bacillus of anthrax and with his discovery of that of tuberculosis; and by the cellular doctrine and abundant labours in pathology of Virchow. Ludwig Brieger then discovered the toxins of certain infections; and Emil A. von Behring completed the sphere of the new study by his discovery of the antitoxins of diphtheria and tetanus. In practical medicine the subsequent results of Behring and his followers have in diphtheria attained a signal therapeutical success. If the striking conceptions of Paul Ehrlich and Emil Fischer continue to prove as fertile in inspiring and directing research as at present they seem to be, another wide sphere of. conceptions will be opened out, not in bacteriology only, but also in biological chemistry and in molecular physics. Again, besides giving us the clue to the nature of many diseases and to the continuity of many morbid series, by bacteriology certain diseases, such as actinomycosis, have been recognized for the first time.

As the prevalence of the conceptions signified and inspired by the word "phlogiston" kept alive ontological notions of disease, so the dissipation of vitalistic conceptions in the field of physics prepared men's minds in pathology for the new views opened by the discoveries of Pasteur on the side of pathogeny, and of J. F. Cohnheim (1839-1884) and of Iliya Metchnikoff on the dynamical side of his- Fevers tology. Of the older ontological notions of disease the strongest were those of the essence of fever and of the essence of inflammation. Broussais had done much to destroy the notion of fever as an entity, but by extravagances in other directions he had discredited the value of his main propositions. Yet, although, as Andral and other French physicians proved, it was extravagant to say that all fevers take their origin from some local inflammation, it was true and most useful to insist, as Broussais vehemently insisted, that "fever" is no substance, but a generalization drawn from symptoms common to many and various diseases springing from many various and often local causes; from causes agreeing perhaps only in the factor of elevation of the temperature of the body. To the establishment of this new conception the improvement and general use of the clinical thermometer gave invaluable advantages. This instrument, now indispensable in our daily work at the bedside, had indeed long been known both to physiologists (Haller) and to clinicians. In the 18th century A. de Haen, and, in the United Kingdom, George Cleghorn (1716-1789) of Dublin and James Currie (1756-1805), carried on the use of the thermometer in fevers; and on the continent of Europe in later years F. G. F. von Barensprung (1822-1865) and Ludwig Traube (1818-1876) did the same service; but it is to the work of Karl August Wunderlich (1815-1877) that we owe the establishment of this means of precision as a method of regular observation both in pathology and in clinical medicine. By his almost exhaustive comparison of febrile movements as symptomatic processes Wunderlich dealt the last blow to the expiring doctrine of the "entity" of "fever"; while on the clinical side Bretonneau and Louis, in 1862-1872, by their careful clinical and pathological studies of forms of fever, relieved the new doctrine of the extravagances of Broussais, and prepared the way for the important distinction of enteric from typhus fever by A. P. Stewart (1813-1883), William Jenner, William Budd (1811-1880), Charles Murchison (1830-1879), J. H. F. Autenrieth (1772-1835), Heinrich Gustav Magnus (1802-1870), Huss and others. By the learned and accomplished Armand Trousseau British and German influences were carried into France.

Meanwhile Cohnheim and Metchnikoff were engaged in destroying the ontological conception not of fever only, but also of inflammation, of which, as a local event, an ontological conception was no less strongly implanted. By his researches on the migration of the white corpuscles of the blood Cohnheim, on the bases laid by Virchow, brought the processes of inflammation within the scope of the normal, seeing in them but a modification of normal processes under perturbations of relatively external incidence; even the formation of abscess was thus brought by him within the limits of perversion of processes not differing essentially from those of health; and "new formations," "plastic exudations," and other discontinuous origins of an "essential" pathology, fell into oblivion. And it is not alien from the present point of view to turn for a moment to the light thrown on the cardio-arterial pulse and the measurement of its motions by the more intimate researches into the phenomena of the circulation by many observers, among whom in the 19th century James Hope, E. J. Marey (1830-1904) and C. F. W. Ludwig will always take a leading place. By them the demonstration of Harvey that the circulation of the blood is in large part a mechanical process, and nowhere independent of mechanical laws, was considerably enlarged and extended. In particular the fluctuations of the pulse in fevers and inflammations were better understood, and accurately registered; and we can scarcely realize now that before Harvey the time of the pulse seems not to have been counted by the watch. Discovery in these various directions then led physicians to regard fever and inflammation not as separable entities, but as fluctuating symptomgroups, due to swervings of function from the normal balance under contingent forces.

As to such reforms in our conceptions of disease the advances of bacteriology profoundly contributed, so under the stress of consequent discoveries, almost prodigious in their extent and revolutionary effect, the conceptions of the etiology of disease underwent no less a transformation than the conceptions of disease itself. It is proper to point out here how intimately a pathology thus regenerated modified current conceptions of disease, in the linking of disease to oscillations of health, and the regarding many diseases as modifications of the normal set up by the impingement of external causes; not a few of which indeed may be generated within the body itself - "autogenetic poisoning." The appreciation of such modifications, and of the working of such causes, has been facilitated greatly by the light thrown upon normal processes by advances in physiology; so dependent is each branch of knowledge upon the advances of contiguous and incident studies. To biological chemistry we have been deeply indebted during the latter half of the 19th century. In 1872, Hoppe-Seyler (1825-1895) gave a new beginning to our knowledge of the chemistry of secretion and of excretion; and later students have increased the range of physiological and pathological chemistry by investigations not only into the several stages of albuminoid material and the transitions which all foodstuffs undergo in digestion, but even into the structure of protoplasm itself. Digestion, regarded not long ago as little more than a trituration and "coction" of ingesta to fit them for absorption and transfer them to the tissues, now appears as an elaboration of peptones and kindred intermediate products which, so far from being always bland, and mere bricks and mortar for repair or fuel for combustion, pass through phases of change during which they become so unfit for assimilation as to be positively poisonous. The formation of prussic acid at a certain period of the vital processes of certain plants may be given as an example of such phases; and poisons akin to muscarin seem to arise frequently in development or regression, both in animals and plants. Thus the digestive function, in its largest sense, is now seen to consist, not only in preparation and supply, but in no small measure also of protective and antidotal conversions of the matters submitted to it; coincidently with agents of digestion proper are found in the circuit of normal digestion "anti-substances" which neutralize or convert peptones in their poisonous phases; an autochthonous ferment, such as rennet for instance, calling forth an anti-rennet, and so on. Now as our own bodies thus manipulate substances poisonous and antidotal, if in every hour of health we are averting selfintoxication, so likewise are we concerned with the various intruding organisms, whose processes of digestion are as dangerous as our own; if these destructive agents, which no doubt are incessantly gaining admission to our bodies, do not meet within us each its appropriate compensatory defensive agent, dissolution will begin. Thus, much of infection and immunity are proving to be but special cases of digestion, and teleological conceptions of protective processes are modified.

Under the name of chemotaxis (W. Pfeffer) are designated certain of the regulative adaptations by which such ends are attained. By chemical warnings the defensive processes seem to be awakened, or summoned; and when we think of the infinite variety of such possible phases, and of the multitude of corresponding defensive agents, we may form some dim notion of the complexity of the animal blood and tissues, and within them of the organic molecules. Even in normal circumstances their play and counterplay, attractive and repellent, must be manifold almost beyond conception; for the body may be regarded as a collective organization consisting of a huge colony of micro-organisms become capable of a common life by common and mutual arrangement and differentiation of function, and by toleration and utilization of each other's peculiar products; some organs, such as the liver, for example, being credited with a special power of neutralizing poisons, whether generated under normal conditions or under abnormal, .which gain entrance from the intestinal tract. As a part of these discoveries has arisen another but kindred doctrine that of hormones (Starling), juices prepared, not for excretion, not even for partial excretion, but for the fulfilment of physiological equilibrium. Thus the reciprocity of the various organs, maintained throughout the divisions of physiological labour, is not merely a mechanical stability; it is also a mutual equilibration in functions incessantly at work on chemical levels, and on those levels of still higher complexity which seem to rise as far beyond chemistry as chemistry beyond physics. Not only are the secreted juices of specialized cells thus set one against another in the body, whereby the various organs of the body maintain a mutual play, but the blood itself also in its cellular and fluid parts contains elements potent in the destruction of bacteria and of their secretions. Thus endowed, the blood, unless overwhelmed by extraordinary invasions, does not fail in stability and self-purification. So various are the conditions of selfregulation in various animals, both in respect of their peculiar and several modes of assimilating different foods, and of protecting themselves against particular dangers from without, that, as we might have expected, the bloods taken from different species, or even perhaps from different individuals, are found to be so divergent that the healthy serum of one species may be, and often is, poisonous to another; not so much in respect of adventitious substances, as because the phases of physiological change in different species do not harmonize; each by its peculiar needs has been modified until, in their several conditions of life, they vary so much about the mean as to have become almost if not quite alien one to another.

In the preservation of immunity then, in its various degrees and kinds, not only is the chemistry of the blood to be studied, but also its histology. By his eminent labours in cellular pathology, Virchow, and Metchnikoff later, gave the last blow to the mere humoral pathology which, after an almost unchallenged prevalence for some two thousand years, now finds a resting-place only in our nurseries. Now the cellular pathology of the blood, investigated by the aid of modern staining methods, is as important as that of the solid organs; no clinical investigator - indeed, apart from research, no practitioner at this day - can dispense with examination of the blood for purposes of diagnosis; its coagulability and the kinds and the variations of the cells it contains being evidence of many def i nitely morbid states of the body. Again, not only in certain diseases may strange cells be found in the blood (e.g. in myelogenic leucaemia), but parasites also, both in man, as those of malaria, of sleeping sickness, of kala-azar, and in animals, as redwater, Texas fever, n'gana, have been discovered, to the great advantage of preventive medicine. For some of these, as redwater (pyrosoma), antidotes are already found; for others, as for Texas fever - of which the parasite is unknown, but the mode of its transmission, by the mosquito, discovered (Finlay-Reed) - preventive measures are reducing the prevalence.

It is obvious that the results of such advances prescribe for the clinical physician methods which cannot be pursued without expert assistance; a physician engaged in busy prac- Spec;a;ism. t i ce cannot himself undertake even the verifications required in the conduct of individual cases. Skill in modern laboratory work is as far out of the reach of the untaught as performance on a musical instrument. In spite, therefore, of the encyclopaedic tradition which has persisted from Aristotle through the Arab and medieval schools down to Herbert Spencer, it is forced upon us in our own day that in a pursuit so manysided as medicine, whether in its scientific or in its practical aspect, we have to submit more and more to that division of labour which has been a condition of advance in all other walks of life. It is now fully recognized that diseases of infants and children, of the insane, of the generative organs of women, of the larynx, of the eye, have been brought successively into the light of modern knowledge by "specialists," and by them distributed to the profession; and that in no other way could this end have been attained. That the division of labour, which may seem to disintegrate the calling of the physician, really unites it, is well seen in the clinical laboratories which were initiated in the later 19th century, and which are destined to a great future. By the approach of skilled pathologists to the clinical wards, a link is forged between practitioners and the men of science who pursue pathology disinterestedly. The first clinical laboratory seems to have been that of Von Ziemssen (1829-1902) at Munich, founded in 1885; and, although his example has not yet been followed as it ought to have been, enough has been done in this way, at Johns Hopkins University and elsewhere, to prove the vital importance of the system to the progress of modern medicine. At the same time provision must be made for the integration of knowledge as well as for the winning of it by several adits. A conspicuous example of the incalculable evil wrought by lack of integration is well seen in the radical divorce of surgery from medicine, which is one of the most mischievous legacies of the middle ages - one whose mischief is scarcely yet fully recognized, and yet which is so deeply rooted in our institutions, in the United Kingdom at any rate, as to be hard to obliterate. That the methods and the subject-matter of surgery and of medicine are substantially the same, and that the advance of one is the advance of the other, the division being purely artificial and founded merely on accidents of personal bent and skill, must be insisted upon at this time of our history. The distinction was never a scientific one, even in the sense in which the word science can be used of the middle ages; it originated in social conceits and in the contempt for mechanical arts which came of the cultivation of "ideas" as opposed to converse with "matter," and which, in the dawn of modern methods, led to the derision of Boyle by Oxford humanists as one given up to "base and mechanical pursuits." Had physicians been brought into contact with facts as hard as those faced by the surgeons of the 16th century (cf. Ambrose Pare), their art would not have lain so long in degradation. It is under this closer occupation with mechanical conditions that surgery to-day is said - not without excuse, but with no more than superficial truth - to have made more progress than medicine. Medicine and surgery are but two aspects of one art; Pasteur shed light on both surgery and medicine, and when Lister, his disciple, penetrated into the secrets of wound fevers and septicaemia, he illuminated surgery and medicine alike, and, in the one sphere as in the other, co-operated in the destruction of the idea of "essential fevers" and of inflammation as an "entity." Together, then, with the necessary multiplication of specialism, one of the chief lessons of the latter moiety of the 19th century was the unity of medicine in all its branches - a unity strengthened rather than weakened by special researches, such as those into "medical" and "surgical" pathology, which are daily making more manifest the absurdity of the distinction. Surgeons, physicians, oculists, laryngologists, gynaecologists, neurologists and the rest, all are working in allotments of the same field, and combining to a common harvest.

While pathology then, which is especially the "science of medicine," was winning territory on one side from physiology,. of which in a sense it is but an aspect, and on another by making ground of its own in the post mortem room Medical  Y g g P Training.  and museum of morbid anatomy, and was fusing these gains in the laboratory so as to claim for itself, as a special branch of science by virtue of peculiar concepts, its due place and provision - provision in the establishment of chairs and of special laboratories for its chemical and biological subdivisions - clinical medicine, by the formal provision of disciplinary classes, was illustrating the truth of the experience that teaching and research must go hand-in-hand, the one reinforcing the other: that no teacher can be efficient unless he be engaged in research also; nay, that for the most part even the investigator needs the encouragement of disciples. Yet it was scarcely until the last quarter of the 19th century that the apprenticeship system, which was a mere initiation into the art and mystery of a craft, was recognized as antiquated and, in its virtual exclusion of academic study, even mischievous. In place of it, systematic clinical classes have become part of the scheme of every efficient school of medicine. A condition of this reform was the need of a preliminary training of the mind of the pupil in pure science, even in physics and chemistry; that is to say, before introduction into his professional studies. The founding of new teaching universities, in which England, and even France, had been at some disadvantage as compared with Scotland and Germany, strengthened the movement in favour of enlarging and liberalizing technical training, and of anticipating technical instruction by some broader scientific discipline; though, as in all times of transition, something was lost temporarily by a departure from the old discipline of the grammar school before a new scheme of training the mind in scientific habits and conceptions was established or fully apprehended. Yet on the whole, even from the beginning, the revolt was useful in that it shook the position of the "learned physician," who took a literary, fastidious and meditative rather than an experimental interest in his profession, and, as in great part a descendant of the humanists, was never in full sympathy with experimental science. At the risk no doubt of some defects of culture, the newer education cleared the way for a more positive temper, awoke a new sense of accuracy and of verification, and created a sceptical attitude towards all conventions, whether of argument or of practice. Among the drawbacks of this temper, which on the whole made for progress, was the rise of a school of excessive scepticism, which, forgetting the value of the accumulated stores of empiricism, despised those degrees of moral certainty that, in so complex a study and so tentative a practice as medicine, must be our portion for the present, and even for a long future, however great the triumphs of medicine may become. This scepticism took form in the school, most active between 1860 and 1880, known as the school of "Expectant Medicine." These teachers, genuinely touched with a sense of the scantiness of our knowledge, of our confidence in abstract terms, of the insecurity of our alleged "facts," case-histories and observations, alienated from traditional dogmatisms and disgusted by meddlesome polypharmacy - enlightened, moreover, by the issue of cases treated by means such as the homoeopathic, which were practically "expectant" - urged that the only course open to the physician, duly conscious of his own ignorance and of the mystery of nature, is to put his patient under diet and nursing, and, relying on the tendency of all equilibriums to recover themselves under perturbation, to await events (Vis medicatrix naturae). Those physicians who had occupied themselves in the study of the exacter sciences, or more closely or more exclusively of the wreckage of the post mortem room, were the strongest men of this school, whether in England or abroad.

But to sit down helpless before human suffering is an unendurable attitude. Moreover, the insight into origins, into initial morbid processes revealed by the pathologists, eu Theraa woke more and more the hoe of dealin with the peutics. hope dealing elements of disease, with its first beginnings; and in the field of therapeutics, chemical and biological experiment, as in the case of digitalis, mercury and the iodides, was rapidly simplifying remedies and defining their virtues, so that these agents could be used at the bedside with more precision. Furthermore, the aversion from drugging had the advantage of directing men's minds to remedies taken from the region of the physical forces, of electricity (G. B. Duchenne, 1806-1875), of gymnastics (Ling, 1776-1839), of hydropathy (V. Priessnitz), of massage (Weir Mitchell), of climate (James Clarke), of diet (R. B. Todd, King Chambers, &c.), and even of hypnotism (James Braid 1 795 ? - 1860), while with the improvement of the means of locomotion came the renewal of the old faith and the establishment of new methods in the use of mineral springs. These and such means, often in combination, took much of the place formerly given to the use of drugs.

Again, a like spirit dictated the use of the physical or "natural" methods on a larger scale in the field of prevention. From the new regard given by physiologists and pathologists to the study of origins, and in the new hopes of thus dealing with disease at its springs, not in individuals only but in cities and nations, issued the great school of Preventive Medicine, initiated in England - E. A. Parkes (1819-1876), J. Simon, Sir B. W. Richardson (1828-1896), Sir H. W. Acland (1815-1900), Sir G. Buchanan (1831-1895), and forwarded in Germany by Max von Pettenkofer (1818-1901). Hygiene became for pathology what "milieu" is for physiology. By the modification of physical conditions on a national scale a prodigious advance was made in the art of preventing disease. The ghastly roll of infantile mortality was quickly purged of its darkest features (Ballard and others); aided by bacteriology, sanitary measures attained some considerable degree of exactness; public medicine gained such an ascendancy that special training and diplomas were offered at universities; and in 1875 a consolidated act was passed for the United Kingdom establishing medical officers of health, and responsible lay sanitary authorities, with no inconsiderable powers of enforcing the means of public health in rural, urban, port and other jurisdictions, with summary methods of procedure. A department of public health was formed within the precincts of the Local Government Board; government laboratories were established, and machinery was devised for the notification of infectious diseases. The enormous growth of towns during the second half of the 19th century was thus attended with comparative safety to these great aggregates of mankind; and the death-rates, so far from being increased, relatively decreased in substantial proportions. In 1878 an act was passed giving like powers in the case of the infectious diseases of animals. The establishment in England of the Register of qualified practitioners and of the General Medical Council (in 1858) did something, however imperfectly, to give unity to the profession, unhappily bisected by "the two colleges"; and did much to organize, to strengthen and to purify medical education and qualification. In 1876 women were admitted to the Register kept by the Council. In 1871 the Anatomical Act of 1832 was amended; and in 1876 the Vivisection Act was passed, a measure which investigators engaged in the medical sciences of physiology and pathology resented as likely to prevent in England the advance of knowledge of living function, both in its normal balance and in its aberrancies, and moreover to slacken that habit of incessant reference of propositions to verification which is as necessary to the clinical observer as to the experimentalist. However the opinion of later generations may stand in respect of the Vivisection Act, it will surely appear to them that the other acts, largely based upon the results of experimental methods, strengthening and consolidating the medical profession, and fortifying the advance of medical education, led directly to a fundamental change in the circumstances of the people in respect of health. The intelligent classes have become far better educated in the laws of health, and less disposed to quackery; the less intelligent are better cared for and protected by municipal and central authority. Thus the housing of the poor has been improved, though this difficult problem is yet far from solution; not the large towns only, but the larger villages also, are cleansed and drained; food has been submitted to inspection by skilled officers; water supplies have been undertaken on a vast scale; personal cleanliness has been encouraged, and with wonderful success efforts have been made to bring civilized Europe back from the effects of a long wave of Oriental asceticism, which in its neglect and contempt of the body led men to regard filth even as a virtue, to its pristine cleanliness under the Greeks and Romans. During the latter half of the 19th century the death-rate of many towns was reduced by something like 50%. Some plagues, such as typhus fever, have been dispelled; others, such as enteric fever, have been almost banished from large areas; and there is much reason to hope that cholera and plague, if introduced, could not get a footing in western Europe, or in any case could be combated on scientific principles, and greatly reduced. Temperance in the use of alcohol has followed the demonstration not only of its unimportance as a food or tonic, but also of its harmfulness, save in very small quantities. In the earlier part of the 19th century, and in remoter districts even in its later years, the use of alcohol was regarded not as a mere indulgence, but as essential to health; the example of teetotallers, as seen in private life and in the returns of the insurance offices, has undermined this prepossession. From the time of Plato medicine has been accused of ministering to the survival of unfit persons, and to their propagation of children. But bodily defect is largely a result of evil circumstances, in the prevention of which the physician is not unsuccessfully engaged, and the growth of sympathy means a stronger cement of the social structure. At any rate the mean standard of health will be raised, perhaps enormously.

In the tropics, as well as in Europe, such methods and such researches threw new light upon the causes and paths of the terrible infections of these climates. In 1880, two years before Koch discovered the bacillus of tubercle, C. L. A. Laveran (b. 1845) discovered the parasite of malaria, and truly conceived its relations to the disease; thus within two years were made two discoveries either of which was sufficient to make the honour of a century. Before the end of the 19th century this discovery of the blood parasite of malaria was crowned by the hypothesis of Patrick Manson, proved by Ronald Ross, that malaria is propagated by a certain genus of gnat, which acts as an intermediate host of the parasite. Cholera (Haffkine) and yellow fever are yielding up their secrets, and falling under some control. The 10th century, by means of this illumination of one of the darkest regions of disease, may diminish human suffering enormously, and may make habitable rich and beautiful regions of the earth's surface now, so far as man's work is concerned, condemned to sterility. Moreover, freedom of trade and of travel has been promoted by a reform of the antiquated, cumbrous, and too often futile methods of quarantine - a reform as yet very far from complete, but founded upon a better understanding of the nature and propagation of disease.

## Special Departments

Hitherto we have presented a survey of the progress of the science and practice of medicine on general. lines; it remains to give some indication of the advance of these subjects of study and practice in particular departments. As regards infections, it is not to be supposed that our knowledge of these maladies has been advanced by pathology and bacteriology only. In the clinical field also it has received a great enlargement. Diphtheria, long no doubt a plague among mankind, was not carefully described until by Pierre Bretonneau in 1826; and since his time our conception of this disease has been extended by the study of later, secondary and incidental phases of it, such as neuritis, which had always formed part of the diphtheritic series, though the connexion had not been detected. Influenza, again, was well known to us in 1836-1840, yet clinical observers had not traced out those sequels which, in the form of neuritis and mental disorder, have impressed upon our minds the persistent virulence of this infection, and the manifold forms of its activity. By the discovery of the bacillus of tubercle, the physician has been enabled to piece together a long and varied list of maladies under several names, such as scrofula and lupus, many of them long suspected to be tuberculous, but now known to belong to the series. It is on clinical grounds that beriberi, scarlet fever, measles, &c., are recognized as belonging to the same class, and evolving in phases which differ not in intimate nature but in the more superficial and inessential characters of time, rate and polymorphism; and the impression is gaining strength that acute rheumatism belongs to the group of the infections, certain sore throats, chorea and other apparently distinct maladies being terms of this series. Thus the field of disease arising not from essential defect in the body, but from external contingencies, is vastly enlarging; while on the other hand the great variability of individuals in susceptibility explains the very variable results of such extrinsic causes. Coincidently therewith, the hope of neutralizing infections by fortifying individual immunity has grown brighter, for it appears that immunity is not a very radical character, but one which, as in the case of vaccination, admits of modification and accurate adjustment in the individual, in no long time and by no very tedious methods. Evidence is accumulating which may end in the explanation and perhaps in the prevention of the direst of human woes - cancer itself, though at present inquiry is being directed rather to intrinsic than to extrinsic causes.

When, leaving the infections, we look for evidence of progress in our knowledge of more or less local diseases, we may begin with the nervous system. It is in this department, from its abstruseness and complexity, that we should expect the advance of anatomy and physiology - normal and morbid - to be most delayed. If we consult the medical works even of the middle of the 19th century we shall find that, in the light of the present time, accurate knowledge in this sphere, whether clinical, pathological or therapeutical, could scarcely be said to exist. Even in the hands of J. A. Lockhart Clarke (1817-1880), one of the earliest investigators of nervous pathology, the improvement of the compound microscope had not attained the achromatism, the penetration and the magnification which have since enabled J. L. C. Schroeder-van der Kolk (1797-1862), Albert von K0111ker, Santiago Ramon y Cajal, C. Golgi (b. 1844) and others to reveal the minute anatomy of the nervous centres; while the discrimination of tissues and morbid products by stains, as in the silver and osmic acid methods, and in those known by the names of Carl Weigert or Marchi, had scarcely begun. In England the Hospital for the Paralysed and Epileptic was founded in 1859, where Charles E. BrownSequard (1817-1894), J. Hughlings-Jackson, Thomas Buzzard, Henry C. Bastian (b. 1837), Sir W. R. Gowers and David Ferrier (b. 1843) found an adequate field for the clinical and pathological parts of their work. In France, in the wards of the Hotel Dieu, Guillaume Benjamin Duchenne (1806-1875), in association with Trousseau and in his private clinic, pursued his memorable clinical and therapeutical researches into the diseases of the nervous system; and Jean M. Charcot (1825-1893) in that great asylum for the wreckage of humanity - the Salpetriere - discovered an unworked mine of chronic nervous disease. M. H. Romberg (1795-1873) and Theodor Meynert (1833-1892) also were pioneers in the study of nervous diseases, but it was not till later in the century that Germany took a high place in this department of medicine. The discoveries of the separate paths of sensory and motor impulses in the spinal cord, and consequently of the laws of reflex action, by Charles Bell and Marshall Hall respectively, in their illumination of the phenomena of nervous function, may be compared with the discovery in the region of the vascular system of the circulation of the blood; for therein a key to large classes of normal and aberrant functions and a fertile principle of interpretation were obtained. Nor was the theory of reflex action confined to the more "mechanical" functions. By G. H. Lewes and others the doctrine of "cerebral reflex" was suggested, whereby actions, at first achieved only by incessant attention, became organized as conscious or subconscious habits; as for instance in the playing on musical or other instruments, when acts even of a very elaborate kind may directly follow the impulses of sensations, conscious adaptation and the deliberate choice of means being thus economized. This law has important ethical and political bearings; but in the province of disease this advance of what may be compared to the interlocking of points and signals has had wide influence not only in altering our conceptions of disease, but also in enlarging our views of all perturbations of function. The grouping of reflex "units," and the paths wherein impulses travel and become associated, have been made out by the physiologist (Sherrington and others) working on the healthy animal, as well as by the record of disease; and not of spontaneous disease alone, for the artificial institution of morbid processes in animals has led to many of these discoveries, as in the method of A. V. Waller (1816-1870), who tracked the line of nervous strands by experimental sections, and showed that when particular strands are cut off from their nutritive centres the consequent degeneration follows the line of the separated strands. By similar methods nature, unassisted, betrays herself but too often; in many instances - probably originating primarily in the nervous tissues themselves - the course of disease is observed to follow certain paths with remarkable consistency, as for instance in diseases of particular tracts of the spinal cord. In such cases the paths of degeneration are so neatly defined that, when the tissues are prepared after death by modern methods, they are plainly to be seen running along certain columns, the subdivisions of which in the normal state may hardly be distinguishable one from another: some run in strips along the periphery of the spinal cord, at its anterior, middle or posterior segments, as the case may be; in other cases such strips occur within its substance, whether along columns of cells or of white matter. It is needless to point out how such paths of disease, in their association with characteristic symptoms, have illuminated the clinical features of disease as well as the processes of normal function.

Not, however, all diseases of the nervous system conduct themselves on these definite paths, for some of them pay no attention to the geography of structure, but, as one may say, blunder indiscriminately among the several parts; others, again, pick out particular parts definitely enough, but not parts immediately continuous, or even contiguous. Diseases of the latter kind are especially interesting, as in them we see that parts of the nervous structure, separated in space, may nevertheless be associated in function; for instance, wasting of a group of muscles associated in function may depend on a set of central degenerations concurring in parts whose connexion, in spite of dissociation in space, we thus perceive. The undiscriminating diseases, on the other hand, we suspect not to be primarily of nervous origin, but to depend rather on the agency of other constituent tissues of this system, as of the blood-vessels or the connective elements. Thus, arguing inversely, we may learn something of the respective natures of these influences and of the way in which the nervous system is affected secondarily.

Yet even the distribution of toxic matters by the blood is not necessarily followed by general and indiscriminate injury to the nervous elements. In infantile palsy, for example, and in tabes dorsalis, there is good reason to believe of  that, definitely as the traces of the disease are found in certain physiologically distinct nervous elements, they are due nevertheless to toxic agents arriving by way of the blood. Here we enter upon one of the most interesting chapters of disorders and modes of disorder of this and of other systems. It has come out more and more clearly of late years that poisons do not betray even an approximately indifferent affinity for all tissues, which indeed a little reflection would tell us to be a priori improbable, but that each tends to fix itself to this cell group or to that, picking out parts for which they severally have affinities. Chemical, physiological and pathological research is exploring the secret of these more refined kinds of "anchorage" of molecules. In 1868 Drs A. Crum Brown and T. R. Fraser proved that by substitution of molecules in certain compounds a stimulant could be converted into a sedative action; thus by the addition of the methyl group CH 2 to the molecule of strychnine, thebaine or brucine, the tetanizing action of these drugs is converted into a paralysing action. The number of these instances, and the variety of them, are now known to be very large; and it is supposed that what is true of these simpler agents is true also of far more elaborate phases of vital metabolism. Now, what is remarkable in these and many other reactions is not only that effects apparently very opposite may result from minute differences of molecular construction, but also that, whatever the construction, agents, not wholly indifferent to the body or part, tend to anchor themselves to organic molecules in some way akin to them. Highly complex as are all animal tissues, or nearly all, yet in this category of high complexity are degrees higher and higher again of which we can form little conception, so elaborate they are, so peculiar in their respective properties, and probably so fugitive. It is this wide range of dynamic peculiarities above the common range of known physical and chemical molecules which excites our wonder; and a reflection of these peculiar properties is seen in their affinities for this or that toxic or constructive agent, whereby the peculiarity, for example, of a particular kind of nerve cell may be altered, antagonized, reinforced or converted. On the other hand, the reagents by which such modifications are apt to be produced are not necessarily simple; many of them likewise are known to be of very high degrees of complexity, approaching perhaps in complexity the molecules to which they are akin. Of such probably are the toxins and antitoxins of certain infections, which, anchoring themselves not by any means indiscriminately, but to particular and concerted molecules, by such anchorage antagonize them or turn them to favourable or unfavourable issues. Toxins may thus become so closely keyed into their corresponding atom groups, as for instance in tetanus, that they are no longer free to combine with the antitoxin; or, again, an antitoxin injected before a toxin may anticipate it and, preventing its mischievous adhesion, dismiss it for excretion. In the mutual behaviour of such cells, toxins, and antitoxins, and again of microbes themselves, we may demonstrate even on the field of the microscope some of the modes of such actions, which seem to partake in great measure at any rate of a chemical quality (agglutinins, coagulins, chemotaxis). It is convenient here to add that such reactions and modifications, if more conspicuous in the nervous system, are of course not confined to it, but are concerned in their degree in all the processes of metabolism, being most readily traced by us in the blood.

Many other diseases formerly regarded as primarily diseases of the nervous system are not such; but, by means of agents either introduced into the body or modified there, establish themselves after the affinities of these in contiguous associated parts of the structure, as in vascular, membranous or connective elements, or again in distant and peripheral parts; the perturbations of nervous function being secondary and consequential. Of such are tetanus and diphtheria, now known to be due to the establishment from without of a local microbic infection, from which focus a toxin is diffused to the nervous matter. The terrible nervous sequels of some forms of inflammation of the membranes of the brain, again, are due primarily to microbic invasion rather of the membranes than of their nervous contents; and many other diseases may be added to this list. The grave palsies in such diseases as influenza, diphtheria, beriberi, or ensuing on the absorption of lead, are in the main not central, but due to a symmetrical peripheral neuritis.

Among diseases not primarily nervous, but exhibited in certain phenomena of nervous disorder, are diseases of the blood-vessels.  Much light has been thrown upon the variations of arterial and venous blood pressures by Karl Ludwig (1816-1895) and his many followers: by them not only the diseases of the circulatory system itself are elucidated, but also those of other systems - the nervous, for instance - which depend intimately on the mechanical integrity of the circulation of the blood as well as on the chemical integrity of the blood itself. With changes of the pressures of the blood in arteries, veins or capillaries, and in the heart itself and its respective chambers, static changes are apt to follow in these parts; such as degeneration of the coats of the arteries, due either to the silent tooth of time, to persistent high blood pressures, or to the action of poisons such as lead or syphilis. Syphilitic lesion of the arteries, and likewise of other fibrous tissues, often involves grave consequential damage to nervous structures fed or supported by such parts. Some of the most successful of the advances of medicine as a healing art have followed the detection of syphilitic disease of the vessels, or of the supporting tissues of nervous centres and of the peripheral nerves; so that, by specific medication, the treatment of paralytic, convulsive, and other terrible manifestations of nervous disease thus secondarily induced is now undertaken in early stages with definite prospect of cure.

Not of. less importance in this respect, and in other disorders many of them of grave incidence, is the knowledge of the phenomena of embolism and of thrombosis, also gained during the latter half of the 19th century - W. S. Kirkes (1823-1864), R. Virchow. By embolism is meant the more or less sudden stoppage of a vessel by a plug of solid matter carried thither by the current of the blood; be it a little clot from the heart or, what is far more pernicious, an infective fragment from some focus of infection in the body, by which messengers new foci of infection may be scattered about the body. Thrombosis is an accident of not dissimilar character, whereby a vessel is blocked not by a travelling particle, but by a clotting of the blood in situ, probably on the occasion of some harm to the epithelial lining of the vessel. Such injuries are apt to occur in syphilitic endarteritis, or senile arterial decay, whereby an artery may be blocked permanently, as if with an embolus, and the area supplied by it, in so far as it was dependent upon this vessel, deprived of nutrition. These events, although far more mischievous in the brain, the functions of which are far-reaching, and the collateral circulation of which is ill-provided, are seen very commonly in other parts.

It is in the structure of the brain itself that modern research has attained the most remarkable success. In 1861 an alleged "centre" of speech was detected, by a combination of clinical and pathological researches, by Paul Broca (1824-1880). By these means also, in the hands of Hughlings-Jackson, and more conclusively by experimental research initiated by G. T. Fritsch (b. 1838) and T. E. Hitzig (b. 1838), but pursued independently and far more systematically and thoroughly by David Ferrier (b. 1843) and his disciples, it was proved that the cerebrum is occupied by many such centres or exchanges, which preside over the formulation of sensations into purposive groups of motions - kinaesthesis of H. Charlton Bastian (b. 1837). The results of these experimental researches by many inquirers into the constitution of the brain have transformed our conceptions of cerebral physiology, and thrown a flood of light on the diseases of the brain. Not only so, but this mapping of the brain in areas of function now often enables the clinical physician to determine the position of disease; in a certain few cases of tumour or abscess, so precisely that he may be enabled to open the skull above the part affected and to extirpate it - operations which are surely a triumph of science and technical skill (Lister, W. MacEwen, V. Horsley).

The remarkable discovery of the dual nature of the nervous system, of its duplex development as a lower and upper system of "neurons," has shed much light upon the problems of practical medicine, but this construction is described under Brain; Neuropathology; Muscle And Nerve, &C.

In mental diseases little of first-rate importance has been done. The chief work has been the detection of chronic changes in the cortex of the brain, by staining and other histological methods, in degenerative affections of this organ - Theodor Meynert (1833-1892), W. Griesinger (1817-1868), Bevan Lewis - and in the separation from insanity due to primary disease or defect of nerve elements of such diseases as general paralysis of the insane, which probably arise, as we have said, by the action of poisons on contiguous structures - such as blood-vessels and connective elements - and invade the nervous matter secondarily. Some infections, however, seem to attack the mental fabric directly; intrinsic toxic processes which may be suspected on the detection of neurin and cholin in the fluids of the brain (F. W. Mott). Truer conceptions of normal psychology have transformed for us those of the morbid - P. Pinel (1745-1826), Griesinger, Henry Maudsley (b. 1835), Mercier, Krapelin, Rivers - and indicated more truly the relations of sanity to insanity. In the treatment of insanity little has been done but to complete the non-restraint system which in principle belongs to the earlier part of the 19th century (Pinel, Tuke, R. G. Hill, J. Conolly). An enormous accumulation of lunatics of all sorts and degrees seems to have paralysed public authorities, who, at vast expense in buildings, mass them more or less indiscriminately in barracks, and expect that their sundry and difficult disorders can be properly studied and treated by a medical superintendent charged with the whole domestic establishment, with a few young assistants under him. The life of these insane patients is as bright, and the treatment as humane, as a barrack life can be; but of science, whether in pathology or medicine, there can be little. A considerable step in advance is the establishment by the London County Council of a central laboratory for its asylums, with an eminent pathologist at its head: from this laboratory valuable reports are in course of issue. Provision for the reception and treatment of insanity in its earliest and more curable stages can scarcely be said to exist. Sufferers from mental disease are still regarded too much as troublesome persons to be hidden away in humane keeping, rather than as cases of manifold and obscure disease, to be studied and treated by the undivided attention of physicians of the highest skill. The care and education of idiots, initiated by Guggenbuhl and others, is making way in England, and if as yet insufficient, is good of its kind.

By the genius of Rene Theophile Laennec (1781-1826), diseases of the lungs and heart were laid on a foundation so broad that his successors have been occupied in detail and refinement rather than in reconstruction. In heart disease the chief work of the latter half of the 19th century was, in the first quarter, such clinical work as that of William Stokes and Peter Mere Latham (1789-1875); and in the second quarter the fuller comprehension of the vascular system, central and peripheral, with its cycles and variations of blood pressure, venous and arterial. Moreover, the intricacies of structure and function within the heart itself have been more fully discriminated (W. H. Gaskell, Aschoff, A. Keith, Wenkebach, J. Mackenzie). By the greater thoroughness of our knowledge of the physics of the circulation - Etienne Marey (b. 1830), Karl Ludwig (1816-1895), Leonard Hill - we have attained to a better conception of such events as arterial disease, apoplexy, "shock," and so forth; and pharmacologists have defined more precisely the virtues of curative drugs. To the discovery of the parts played in disease by thrombosis and embolism we have referred above. With this broader and more accurate knowledge of the conditions of the health of the circulation a corresponding efficiency has been gained in the manipulation of certain remedies and new methods of treatment of heart diseases, especially by baths and exercises.

As regards pulmonary disease, pneumonia has passed more and more definitely into the category of the infections: the modes of invasion of the lungs and pleura by tuberculosis has been more and more accurately followed; and the treatment of these diseases, in the spheres both of prevention and of cure, has undergone a radical change. Instead of the close protection from the outer air, the respirators, and the fancy diets of our fathers, the modern poitrinaire camps out in the open air in all weathers, is fed with solid food, and in his exercise and otherwise is ruled with minute particularity according to the indications of the clinical thermometer and other symptoms. The almost reckless reliance on climate, which, at Davos for instance, marked the transition from the older to the modern methods, has of late been sobered, and supplemented by more systematic attention to all that concerns the mode of life of the invalid. The result is that, both in physicians and in the public, a more hopeful attitude in respect of the cure of phthisis has led to a more earnest grappling with the infection in its earliest stages and in every phase, with a correspondingly large improvement in prevention and treatment. Indeed, in such early stages, and in patients who are enabled to command the means of an expensive method of cure, phthisis is no longer regarded as desperate; while steps are being taken to provide for those who of their own means are unable to obtain these advantages, by the erection of special sanatoriums on a more or less charitable basis. Perhaps no advance in medicine has done so much as the study of tuberculosis to educate the public in the methods and value of research in medical subjects, for the results, and even the methods, of such labours have been brought home not only to patients and their friends, but also to the farmer, the dairyman, the butcher, the public carrier, and, indeed, to every home in the land.

It was in the management of pleurisies that the aid of surgical means first became eminent in inward disease. In the treatment of effusions into the pleura and, though with less advantage, of pericardial effusions, direct mechanical interference was practised by one physician and another, till these means of attaining rapid and complete cure took their places as indispensable, and were extended from thoracic diseases to those of the abdominal and other inner parts formerly beyond the reach of direct therapeutics. Lord Lister's discoveries brought these new methods to bear with a certainty and a celerity previously undreamed of; and many visceral maladies, such as visceral ulcers, disease of the pancreas, stone of the kidney or gall-bladder, perityphlitis, ovarian dropsy, which in the earlier part of the 19th century were either fatal or crippling, are now taken promptly and safely in hand, and dealt with successfully. Even for internal cancer cure or substantial relief is not infrequently obtained. We have said that this advance is often quoted, not very wisely, to signify that in modern progress "medicine" has fallen behind surgery - as if the art of the physician were not one and indivisible. That certain Fellows of the College of Physicians (especially in gynaecology) have personally taken operative procedures in hand is some good omen that in time the unreal and mischievous schism between medicine and surgery may be bridged over.

In the department of abdominal disease progress has been made, not only in this enormous extension of means of cure by operative methods, but also in the verification of diagnosis. The first recognition of a disease may be at a necropsy, but then usually by irresponsible pathologists; it is another matter when the physician himself comes under rebuke for failing to seize a way to cure, while the chance remained to him, by section of the abdomen during life. The abdomen is still "full of surprises"; and he who has most experience of this deceptive region will have least confidence in expressing positive opinions in particular cases of disease without operative investigation. Besides the attainments mentioned above, in respect of operative progress, many important revisions of older rule-of-thumb knowledge have come about, and not a few other substantial discoveries. Among the revisions may be adduced some addition to our knowledge of dyspepsia, attained by analytic investigations into the contents of the stomach at various stages of digestion, and by examining the passage of opaque substances through the primae vine by the Rontgen rays. Thus the defects, whether of this secretion or of that, and again of motor activity, the state of the valvular junctions, the volume of the cavities, and their position in the abdomen, may be ascertained, and dealt with as far as may be; so that, although the fluctuations of chemical digestion are still very obscure, the application of remedies after a mere traditional routine is no longer excusable. In our conceptions of the later stages of assimilation and of excretion, with the generation of poisons (auto-intoxication) in the intestinal tract, there is still much obscurity and much guess-work; yet in some directions positive knowledge has been gained, partly by the physiologist, partly by the physician himself. Of such are the better understanding of the functions of the liver in normal catabolism, in the neutralization of poisons absorbed from the intestines or elsewhere, in the causation of jaundice, and in diabetes [Bernhardt Naunyn (b. 1839) and F. W. Pavy]. Nor must we forget the unfolding of a new chapter of disease, in the nosology of the pancreas. In diabetes this organ seems to play a part which is not yet precisely determined; and one fell disease at least has been traced to a violent access of inflammation of this organ, caused perhaps by entry of foreign matters into its duct. The part of the pancreas in digestion also is better understood. The part of the spleen in the motley group of dyspepsias and anaemias, conspicuous as it often is, still remains very enigmatic.

The peritoneum is no longer regarded with awe as inviolable; by modern methods, if not as manageable as other lymphatic sacs, it is at any rate accessible enough without considerable risk to life. Not only in its bacteriological relations are the conditions of peritonitis recognized in its various kinds, but also the state known as "shock" turns out to be quasi-mechanical, and avoidable by measures belonging in considerable part to this category. Thus, by the avoidance both of toxaemia and of shock, peritonitis and other dangers of the abdomen, such as strangulations or intussusceptions of the bowels, formerly desperate, can in many cases be dealt with safely and effectively.

Our knowledge of diseases of the kidneys has made no great advance since the time of Richard Bright. In the sphere of physiology and in the interpretation of associated arterial diseases much obscurity still remains; as, for instance, concerning the nature of the toxic substances which produce those bilateral changes in the kidneys which we call Bright's disease, and bring about the "uraemia" which is characteristic of it. Lardaceous disease, however, here and in other regions, now appears to be due to the specific toxins of pyogenetic micro-organisms. In stone of the kidney a great advance has been made in treatment by operative means, and the formation of these stones seems to recent observers to depend less upon constitutional bent (gout) than upon unhealthy local conditions of the passages, which in their turn again may be due to the action of microorganisms.

To Thomas Addison's descriptions of certain anaemias, and of the disease of the suprarenal capsules which bears his name, something has been added; and W. Hunter's researches on the severer anaemias are doing much to elucidate these subtle maladies. And on the influence of these inconspicuous bodies and of the pituitary body in sustaining arterial blood pressures physiologists have thrown some important light.

The secret of the terrible puerperal septicaemia was read by J. P. Semmelweiss (q.v.), wherein he proved himself to be the greatest of Lister's forerunners (see Lister).

The diseases peculiar to women (see Gynaecology) have received attention from early times, but little progress had been made in their interpretation till the 19th century. In the middle part of the century, by a natural exaggeration of the importance of newly-discovered local changes in the pelvic organs, much harm was done to women by too narrow an attention to the site, characters and treatment of these; the meddlesomeness of the physician becoming in the temperament of woman. a morbid obsession. To James Matthews Duncan (1826-1890) we chiefly owe a saner and broader comprehension of the relative importance of the local and the general conditions which enter into the causation of uterine and ovarian disorders. In operations for diseases of the pelvis, ovarian dropsy, cancer of the uterus, and other grave diseases of the region, success has been stupendous.

In the subject of diseases of the skin much has been done, in the minuter observation of their forms, in the description of forms previously unrecognized, and in respect of bacterial and other causation and of treatment. The comparison of observations in various climates and peoples has had some weight; while in the better knowledge of their causes their treatment has found permanent advantage. Not only is the influence of bacteria in the causation of many of them newly revealed, but it is now recognized also that, even in skin diseases not initiated by microbic action, microbes play a considerable and often a determining part in their perpetuation; and that the rules of modern aseptic surgery are applicable with no little success to skin therapeutics. We have learned that "constitutional" causes play a smaller part in them than was supposed, that a large number of diseases of the skin, even if initiated by general disorder, are or soon become local diseases, being, if not initiated by local infection yet perpetuated thereby, so that, generally speaking, they are to be cured by local means.

The diseases of children have not lacked the renewed attention, the successful investigation, and the valuable new lights which have been given to other departments of medicine. That infantile paralysis is an infection, and that its unhappy sequels are now treated with more hope of restoration, has been indicated already. Infantile diarrhoea has also been recognized as a common infection (Ballard), and the means of its avoidance and cure ascertained. The conditions of diet and digestion in children are now far better understood, and many of their maladies, formerly regarded as organic or incomprehensible, are cured or prevented by dietetic rules. Rickets, scurvy and "marasmus" may be instanced as diet diseases in children. Acute inflammation of the ear, with its alarming extensions to the cerebral. cavity, is now dealt with successfully by surgical means, and infected sinuses or even encephalic abscesses are reached and cleansed. The origins, kinds and processes of meningitis are more clearly distinguished, and referred each to its proper cause - for the most part bacterial.

As by the discovery of stethoscopy by Laennec a new field of medical science and art was opened up, so, more recently, inventions of other new methods of investigation in medicine have opened to us other fields of little less interest and importance. Of such is the ophthalmoscope, invented by H.

von Helmholtz in 1851. By the revelations of this instrument not only have the diseases of the eye been illuminated, but much light has been thrown also upon the part of the eye in more general maladies; as, for instance, in syphilis, in diabetes, in kidney diseases, and in diseases of the brain - F. C. Donders (1818-1889), Alfred von Grafe (1830-1899) and others. A remarkable help to the cure of headaches and wider nervous disorders has come out of the better appreciation and correction of errors of refraction in the eye. Radiography has done great things for surgery; for medicine its services are already appreciable, and may prove more and more valuable hereafter. In 1879 the use of the spectroscope in medicine was pointed out by Dr Charles A. MacMunn (b. 1852). By E. du Bois-Reymond, Robert Remak (1815-1865), Carlo Matteucci (1811-1868), Guillaume Duchenne (1806-1875), the value of electricity in medicine, greater in diagnosis perhaps than in therapeutics, was demonstrated. By the sphygmograph (E. J. Marey, 1863) attention was drawn to the physical features of the circulation, to the signs of degeneration of the arterial tree, and less definitely to the fluctuations of blood pressure; but as we have said under the consideration of diseases of the heart, the kymographs of Ludwig and his pupils brought out these fluctuations far more accurately and completely. By these, and other instruments of precision, such as the thermometer, of which we have already spok en, the eminently scientific discipline of the measurement of functional movements, so difficult in the complex science of biology, has been cultivated. By the laryngoscope, invented about 1850 by Manuel Garcia the celebrated singingmaster, and perfected by Johann Czermak (1828-1873) and others, the diseases of the larynx also have been brought into the general light which has been shed on all fields of disease; and many of them, previously known more or less empirically, submitted to precise definition and cure. Of such we may cite tuberculosis of the larynx, formerly as incurable as distressing; and "adenoids" - a disease revealed by intrascopic methods - which used grievously to thwart and stifle the growth both of mind and body in children, are now promptly removed, to the infinite advantage of the rising generation. To the value of stains in clinical diagnosis, especially in investigation of perversions of the blood in many maladies, we have already made some reference. The discovery of the Rontgen rays has also extended the physician's power of vision, as in cases of aortic aneurysm, and other thoracic diseases.

By photography and diagrammatic records the clinical work of hospital wards has been brought into some better definition, and teaching made more accurate and more impressive. The separation of the alkaloids belongs rather to the earlier part of the 19th century, but the administration of these more accurate medications by means of hypodermic injection (see Therapeutics) belongs to the latter. The ancient practice of transfusion has been placed on a more intelligible footing, and by the method of saline injections made more manageable as a means of relief or even of cure. Finally, calculation by statistics (William Farr, Karl Pearson, and others) has been brought into line with other scientific methods: the method is a difficult one, and one full of pitfalls for the unwary, yet when by co-operation of physician and mathematician its applications have been perfected its services will appear more and more indispensable.

Among the achievements of the medicine of the 19th century the growth of the medical press must not be forgotten. In England, by the boldness of the Lancet (founded in 182 3), the tyranny of prescription, inveterate custom, and privilege abused was defied and broken down; freedom of learning was regained, and promotion thrown open to the competent, independently of family, gild and professional status. For the record and diffusion of rapidly growing knowledge, learned societies, universities and laboratories, greatly increased in number and activity, issue their transactions in various fields; and by means of yearbooks and central news-sheets the accumulation of knowledge is organized and made accessible.

It is interesting to find that, with all this activity in the present reformed methods of research and verification are not confined to the work of the passing day; in the brilliant achievements of modern research and reconstruction the maxim that "Truth is the daughter of Time" has not been forgotten. In the field of the History of Medicine the work of scholars such as Francis Adams of Banchory (1796-1861), William A. Greenhill (1814-1894) and C. Creighton in England, Maximilien P. Littre (1801-1881) and Charles V. Daremberg (1817-1872) in France, and Heinrich Haser (1811-1888) and August Hirsch, Diels, Weltmann and Julius Pagel in Germany, will prove to our children that tradition was as safe in our hands as progress itself.

(T. C. A.) Bibliography. - Osler and McCrae, Modern Medicine; F. T. Roberts, The Practice of Medicine (1909); Hermann Nothnagel, Internationale Beitrcige zur inneren Medicin (1902); Ed. Brovardel, Traite de medecine (1895-1902); T. D. Savill, Clinical Medicine  (1909); W. Osler, The Principles and Practice of Medicine (1909); Allbutt and Rolleston, A System of Medicine (1906-1910); Sir Patrick Manson, Tropical Medicine (1907); Frederick Taylor, A Manual of the Practice of Medicine (1908).