# Popular Science Monthly/Volume 79/September 1911/On the History of Internal Medicine

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* ON THE HISTORY OF INTERNAL MEDICINE
By JOHN BENJAMIN NICHOLS, M.D.
WASHINGTON, D. C.
AS a subject of general rather than of technical interest appropriate to this occasion, I propose to present a brief historical survey and some considerations relating to the development of internal medicine.
One of the primitive tendencies of human nature is the development and employment of procedures aiming at the relief of personal ailments and injuries. It is probable that all peoples have to a greater or less extent developed something in the way of therapeutic practises. In primitive stages of culture some agents of efficiency may have come into domestic and popular use; but the chief development of medicine in primitive societies has been in association with religious cults or superstitious observances. Originally medical practise was mainly a function of the priesthood. Even under such conditions the powerful force of psychotherapy must have been brought into action so as to be of benefit to distressed humanity.
Ancient writings have preserved to us some account of the therapeutic methods in vogue in the earliest historic civilizations, such as the Egyptian, Jewish, Babylonian, Assyrian, Indian, Chinese, etc.: among these medicine was chiefly practised by the priests. It was among the Greeks, however, and especially by Hippocrates and his associates 2,300 years ago, that the foundations were laid from which through a continuous line of existence and evolution can be traced the development of civilized medicine to its present state. Probably from the Egyptians and other antecedent and neighboring nations were derived some contributions to Greek medicine, but the derivation is not now clearly traceable, and practically the school of Hippocrates stands as the originator of the present era of medicine. Since his time the development of internal medicine has been intimately involved in four great epochs or movements of civilization and thought, so that its history is divisible into the following corresponding grand epochs:
1. Greek (also Roman and Byzantine) medicine; from before 500 B.C. to the fall of the Roman Empire,—A.D. 476 (Rome), 640 (Alexandria), 1453 (Byzantium).
2. Arabian medicine; about 750 to 1200 A. D.
​3. Medieval medicine; about 500 to 1825. Monastic medicine; 500 to 1200. Scholastic medicine; 1200 to 1600. Systematic medicine; 1600-1825.
4. Modern medicine; since about 1825.
Greek Medicine.—The early medicine of the Greeks, as of other peoples, had mythologic and theologic characteristics. The god of medicine among them was Asclepios, or (Latinized) Æsculapius, who perhaps was a real physician flourishing prior to 1000 B.C. The temples devoted to his cult, called Asclepieia, were located in salubrious situations, or at mineral springs; invalids resorted to these institutions in large numbers, and were ministered to by the physician-priests. Famous Asclepieia were situated at Cnidos, Cos, Epidaurus, Pergamus, Tricca, Mycenæ and Sicyon. Gradually there developed in connection with these institutions associations or guilds of physicians called Asclepiadas, who devoted their entire time to medical practise and instruction and had no priestly functions. The separation and differentiation of the functions of the physicians from the priesthood marked an important step in the evolution of medicine, as it left medicine and the medical profession free to develop along independent lines, entirely dissociated from priestcraft. These associations of Asclepiadæ formed schools for medical instruction and were centers of medical thought and influence. Such schools or guilds were located in Cnidos (Asia Minor), Cos (one of the Ægaean Islands), Rhodes, Cyrene (north Africa), and Crotona (Italy). The two most noted were those of Cnidos and Cos. Literary remains from the school of Cnidos have probably survived in the Hippocratic writings; while the school of Cos, which was flourishing prior to 500 B.C., produced the illustrious Hippocrates.
Hippocrates lived from about 460 to 377 B.C., a period when Greek culture and civilization were at their zenith. Originally trained in the temple and school of Cos, he traveled extensively and resided and practised in various places. His fame is derived from his writings. Of the works attributed to him, about sixty in number, only some ten to seventeen are regarded by the critics as being indisputably his production, the rest having been written by others before and afterward.
The Hippocratic writings constitute a systematic and comprehensive presentation of medical and surgical observations, doctrines and practise. Especial attention was given to prognosis, dietetics and meteorological conditions as causes 'of disease; and the beginning was presented of the humoral pathology, which for ages dominated medicine. All this mass of knowledge and doctrine could hardly have been discovered or elaborated by Hippocrates himself, but was probably mainly the accumulated knowledge of his predecessors first placed in literary form by him, and illuminated by his own keen observation, criticism and individuality.
​There is little in the writings of Hippocrates of direct value to us to-day; yet while crude, imperfect, and visionary, they were of profound importance in the development of medicine. They constitute the first systematic literary presentation of pure medical science and art, aside from sacerdotal systems. They were, for the time, a very creditable beginning toward the development of rational medicine; and had progress in the subsequent ages been as substantial as that in the brief time prior to Hippocrates, the history of internal medicine for the ensuing two thousand years would not have been one of stagnation and inefficiency. Hippocrates showed himself to be a keen observer of clinical phenomena, a master clinician, and the part of his work of permanent value was the accumulation of clinical facts by observation, or the empirical method of developing medical knowledge which time has shown to be the only efficient method. Hippocrates displayed the noblest conception of the medical vocation, and in this, with his method of developing clinical knowledge, he set a standard and example for all time.
The doctrines of Hippocrates did not immediately gain general acceptance; soon after his death they nearly fell into oblivion, but six centuries later they were revived and given a vogue by Galen and then attained a dominant influence which they continued to exercise until the dawn of the modern era. During the interval between Hippocrates and Galen (B.C. 400 to 200 A.D.) a number of medical systems developed and continued in force for varying periods. The principal of these systems were:
1. The Dogmatic School.—This, based on the theories of Plato (B.C. 427-347), was developed by the immediate successors of Hippocrates, but it survived for only a few decades. The doctrines of this sect were highly speculative, and the humoral pathology was a fundamental tenet.
2. The school or following of Herophilus, originally located in Alexandria, flourished about B.C. 290 to A.D. 100. Herophilus, its founder, lived about 335-280 B.C., was one of the earliest anatomical investigators, and in part followed Hippocrates.
3. The school of Erasistratus, a famous contemporary and rival of Herophilus, also of Alexandria. His following flourished about B.C. 280 to A.D. 200.
4. The Empirical School, which existed about B.C. 280 to A.D. 117, was based on the skeptical philosophy of Pyrrho (B.C. 376-288). It rejected hypothetical speculations on the underlying causes and nature of phenomena, and recognized as valid only such knowledge as was derived from observation and experience. This school, therefore, had the only successful method of developing knowledge, identical with the modern inductive and scientific method, but it was not acceptable to the ancient and medieval habits of thought.
​5. The Methodist School was founded by Asclepiades (B.C. 128-56) and his pupil Themison. It was an application of the atomic philosophy of Leucippus and Democritus to medicine, holding that vital and morbid phenomena depended on the movements of atoms or particles through pores in the body. The methodist doctrines exerted a strong influence on medical thought for many centuries.
6. The Pneumatic System, about A.D. 70 to 160, was founded and chiefly represented by Athenæus of Attalia. Its pathology was based on an aerial or gaseous principle.
7. The Eclectics, who date from about 50 A.D., had no common or distinctive views, but individually developed widely differing systems. Among them were included some of the most eminent physicians of antiquity. Aretæus (about 30-90 A.D.) was one of the earliest and most distinguished. Two other eminent writers of about that period deserve mention, namely, Celsus (about 30 B.C. to 50 A.D.), a brilliant encyclopedic writer on medicine, and Dioscorides (40-90 A.D.), who wrote a treatise on materia medica which remained an authority almost to modern times.
The greatest of the Eclectics was Claudius Galen (about 131-206 A.D.), of Pergamus and Rome. He received an exhaustive education at Pergamus (in Asia Minor), and other educational centers, and especially at Alexandria. He was a most prolific writer, not only on medicine but on other subjects, his works numbering between three and four hundred. He made important and extensive original contributions on anatomy and pharmacology. In internal medicine his system to a considerable extent was a revival and amplification of the doctrines of Hippocrates. So powerful was his influence that for nearly fifteen centuries Hippocrates and Galen continued the main authorities and basis of medicine.
Prom about the second century B.C. Greece and the entire civilized world of that time had come under Roman dominion; but though the political administration was Roman the culture and civilization of the Roman Empire was of Greek origin and character. The early medicine of the Romans was very crude, consisting mainly of superstitious observances under the auspices of soothsayers and priests; and there was no important Roman addition to medical knowledge. Later, Greek medicine and practitioners were introduced among the Romans, and prevailed until the fall of the Empire. Asclepiades (B.C. 128-56), the founder of the methodist school, was one of the main agents in establishing Greek medicine in Rome. Alexandria was for centuries the greatest center and headquarters of learning and education of the ancient world; it contained a vast library and produced important systems of philosophy and medicine.
Subsequent to Galen medicine in the Roman Empire came to a ​standstill or suffered decline, and the few writers who attained any note were little more than compilers of and commentators on the more ancient authorities. Greco-Roman medicine came to an end in the west with the fall of Rome in 476 A.D., while the capture of Alexandria and burning of its great library by the Arabians about 640 ended the intellectual influence of that city. In the Eastern or Byzantine Empire, Greek medicine continued for a longer time, overlapping the Arabian period. Among the important writers or compilers of this later (post-Galenic) period may be mentioned Oribasius (A.D. 326-403), Alexander of Tralles (525-605), and Paul of Ægina or Paulus Æginæta (about 600). Ultimately Greco-Byzantine medicine declined with the decay of the Eastern Empire, its last distinguished exponent being John Actuarius (died 1283); and the last remnant of the Roman Empire and of direct Greek influence came to an end with the capture of Constantinople by the Turks in 1453.
Arabian Medicine.—Soon after the Roman Empire fell, another people, the obscure Arabian tribes, energized by the religion founded by Mahomet, burst forth and established a vast dominion under whose fostering care enlightenment and learning were carried along during the centuries while Europe floundered in darkness and chaos. The Moslem era is dated from the Hegira, or flight of Mahomet from Mecca, in 622. Within a few years from this the Arabians, organized and inspired by the new religion, overran and conquered western Asia, northern Africa, and Spain, and over that wide territory established a dominion that lasted for six centuries. This dominion soon broke up into two independent divisions or sovereignties, the eastern Caliphate, embracing the Asiatic territories, and the western Caliphate, in Spain. About 750 two enlightened dynasties were founded, one in the east with its capital at Bagdad, the other in Spain with its capital at Cordova, both of which encouraged and developed culture and education to a high plane. The Moorish dominion in Spain was broken in 1212, and the eastern Caliphate was overthrown by the Mongols in 1258. The Arabian period of culture therefore covered the years from about 750 to 1200.
During this period the Arabian scholars collected and translated the learning of the Greeks, Persians and Indians, and cultivated the arts and sciences, especially architecture, philosophy, mathematics, astronomy, geography, alchemy and medicine. In some branches they made notable advances, as in mathematics; but in the main their chief service was more in conserving the learning of the past than in creating new knowledge. Important schools, libraries and hospitals were established, especially at Bagdad and Cordova, but also at Damascus, Samarcand, Bokhara, Seville, Toledo, Granada and numerous other cities.
In medicine the Arabians displayed great interest and proficiency, ​and they produced a large number of writers and authorities on this subject. These were mainly translators, compilers and commentators of the Greek medical writings, so that their chief service to medicine was the preservation and transmission to succeeding ages of Greek medical lore; although they did make some material contributions in the differentiation of eruptive fevers and the introduction of certain drugs. The Arabians adhered quite closely to the authority of Galen. Of the large number of known Arabian medical writers three stand preeminent, Ehazes (850-932) and Avicenna (980-1037) of Bagdad, and Averroes (1126-1198) of Cordova.
Medieval Medicine.—During the four or five centuries following the fall of Borne (476), known in history as the Dark Ages, medicine in Europe shared in the general intellectual torpor of the period. No eminent medical writer or practitioner appears in the annals of Christendom during this time. It is probable that the traditions and practise of Greek medicine gradually declined and the practitioners of the art became greatly degraded from their former standing. Ultimately medical and surgical practise came largely into the hands of members of religious orders (monastic medicine).
The revival of medical science in medieval Europe dates from the development of the famous secular medical school and university of Salerno in Italy, the first of the great European universities. Salerno was a salubrious town and health resort located on the seacoast a short distance southeast of Naples. The origin of the medical school at Salerno is obscure; it may have been founded by Charlemagne, and it is also supposed to have had early relations with the famous Benedictine monastery of Monte Cassino, north of Naples, which was itself a seat of a hospital and monastic medical school. The propinquity of Salerno to Sicily, which for a time was under Saracen dominion, made the Arabian influence accessible. The school of Salerno was in operation by the middle of the ninth century (846), Greek (Hippocratic) medicine being cultivated. The most famous and influential of its earlier teachers was Constantinus Africanus (1018-1087) of Carthage, who had traveled and studied extensively, and is credited with having introduced Arabian learning into Europe; he later became a monk at Monte Cassino. The school at Salerno was at the height of its fame and influence, which extended all over Europe, during the eleventh and twelfth centuries, but after the establishment of the great European universities in the thirteenth century it lost its preeminence and rapidly declined, though it continued in nominal existence until the nineteenth century.
The second European medical school was that of Montpellier, near the Mediterranean coast of France. The date of its establishment is unknown, but it was in operation in 1137; it attained the highest repute as a medical school, and has ever since continued in a flourishing and ​influential existence. There was a celebrated hospital at Montpellier, taking advantage of the salubrious climate of the Riviera, and its proximity to Spain made the Moorish learning accessible.
The thirteenth century, in which occurred the downfall of Arabian empire and culture, saw in Europe a great intellectual revival. Many great universities were founded within a few decades from the year 1200, such as those of Bologna, Padua, Naples and Rome in Italy, Paris, Orleans and Toulouse in Prance, Oxford and Cambridge in England, and others. The medical instruction given in these institutions, and in others founded later, has ever since been the fountain of medical knowledge for the world and conferred upon the medical profession the stamp of learning and repute.
During the middle ages medicine shared in the intellectual characteristics of the period. It was an age of dogmatism and intellectual narrowness; the church exercised a censorship over all thought, and all tendency to mental independence and originality was repressed. The empirical method of gaining knowledge, that is, the accumulation of facts by direct and careful observation and study of natural phenomena, was rejected. This method was too slow and laborious, and left too many blanks in knowledge, to be acceptable. The ancient and medieval philosophers preferred to construct complete schemes of the universe out of their own minds, and took such pride in these brilliant creations of their own intellects, and regarded them as so complete and perfect, that observation of nature was regarded as superfluous and unnecessary. Men engaged in fine-spun controversies over metaphysical and theological subtleties and dwelt on the unimportant and unreal trivialities of their subjective philosophies, to the neglect of the important and real things of the objective world. Schools were plentiful and vigorous; but they were under the ecclesiastical control and influence, and simply fostered the scholastic dogmatism and dialectics. There were men in those days with as great intellects as the world has ever produced; but they frittered away their gigantic powers on inane trivialities. Dogmas and authorities were rigidly adhered to, originality and innovations were repressed, and for centuries mental advancement was inhibited.
Medieval medicine displayed all these characteristics (scholastic medicine). The doctrines of the ancients, especially Galen and Hippocrates, and of the Arabians were rigidly followed, and until the Renaissance there was no change and no progress. Medical thought was dominated by the humoral pathology or theory of disease, which had appeared as early as in the writings of Hippocrates. According to this theory health consisted in a perfect combination and action of the elements and humors of the body, while disease resulted from a derangement or corruption of them. Pour humors were recognized, mucus, blood, bile (yellow bile) and black bile (atrabile). Mucus was ​supposed to be secreted by the brain, and by flowing downward ("defluxions") into the respiratory and alimentary passages produced catarrhal and other diseases. Black bile was an entirely fanciful secretion of the adrenals. In crude or corrupted state the humors were supposed to be "acrid"—toxic or morbific; during the course of the disease they were believed to undergo a process of ripening or digestion—"coction" as it was called—to be finally expelled from the body at the crisis of the disease. The aim of treatment was to remove the acrid humors, or to promote their concoction and expulsion. Free bloodletting and other vigorous depleting measures were in general use.
About the sixteenth century began the great awakening of the world known as the Renaissance, which marks the end of the middle ages and the beginning of the modern era. This movement brought about a revolution in medical thought and yielded enormous acquisitions of medical knowledge.
The awakening in medicine was first manifested, in the sixteenth century, in the development of anatomical knowledge, as we have it to-day, under Vesalius (1514-1564), Jacobus Sylvius (1478-1555), Eustachius (1500-1574), Fallopius (1523-1562) and their successors, many of whose names are immortalized in our anatomical nomenclature more enduringly and more nobly than by monuments of bronze. The sixteenth century saw the labors of Ambroise Paré (1509-1590), the father of modern surgery, and important contributions in obstetrics and gynecology. In the seventeenth century modern microscopy was developed, and modern physiology may be said to have been founded by the epochal discoveries of William Harvey (1578-1657) relating to circulation and generation.
In the domain of internal medicine the Renaissance of the sixteenth century effected a revolution in, or release from, the rigid and dogmatic doctrines previously current. Nevertheless, the new doctrines were no nearer true or more effective than the old, and for three centuries longer internal medicine was destined to remain at a standstill before it too was really born into the family of modern sciences.
The first change was the overthrow of the authority of Galen (and the Arabians), which had previously been the main support of medical thought. This was brought about partly by the exact researches of Vesalius disclosing the errors in the anatomical teachings of Galen, partly by the effusions of the spectacular and mystical Paracelsus (14931541). The authority of Hippocrates continued to have weight for a much longer time.
Subsequent to Paracelsus and the break up of the ancient and Arabian medicine there developed a succession of speculative systems or schools of medical doctrine and practise, each of which had more or less general acceptance for a while, only to die out and be superseded by ​its successors (systematic medicine). These systems were developed by distinguished teachers or writers, were usually mutually antagonistic, and left but little impress of abiding value or truth upon internal medicine. The chief of these medical systems were as follow: In the seventeenth century:
1. The mystical system of Van Helmont (1578-1644), in which such factors as the fall of man, spirits, demons and witches figured as causes of disease; this system was a sort of recasting of the doctrines of Paracelsus.
2. The Iatrochemical system, originated by Franciscus Sylvius (1614—1672), attributed the phenomena of disease to chemical causes (as excess of acid or of alkali); but the chemical ideas underlying the system were crude and fantastic.
3. The Iatrophysical (Iatromechanical or Iatromathematical) system, originated by Sanctorius (1561-1635) or more especially by Borelli (1608-1679), explained physiologic and pathologic processes as brought about by the physical and mechanical activities of the body structures, and employed precise methods for measuring those activities. This system had considerable following, and while it may have contributed to physiologic knowledge it was ineffective as a basis for therapeutics.
4. The system of Thomas Sydenham (1624-1689), of England, who largely followed Hippocrates.
In the eighteenth century:
5. The eclectic doctrines of Herman Boerhaave (1668-1738), of Holland; he was preeminently a clinician, and in his day was the most celebrated practitioner of Europe.
6. Animism, the spiritualistic system of Georg Ernest Stahl (1660-1734).
7. The system of Friedrich Hoffmann (1660-1742), based on the mechanical and motor activities of the body.
8. The system of William Cullen (1712-1790), based especially on the nervous activities of the body.
9. The "Old Vienna School," founded by Gerhard van Swieten (1700-1772), and having Maximilian Stoll (1742-1787) as a distinguished adherent; this school largely followed a humoral pathology, akin to the doctrines of Hippocrates, Sydenham and Boerhaave.
10. The doctrine of "infarctus," introduced by Johann Kämpf (published 1780), according to which diseases in general were due to fecal impactions (or "infarcts") and therapeusis was based on rectal irrigation.
11. Vitalistic systems, based on the activities of the "vital force," supported by Bordeu (1722-1776), Barthez (1734-1806) of the school of Montpellier, Reil (1759-1813) of Germany, Bichat (1771-1802) of France, and others.
​12. Brunonianism, founded by John Brown (1735-1788) of Scotland, based on the doctrine that vital and morbid processes depend on irritability or stimulations varying in intensity. It continued into the nineteenth century, especially in Germany and Italy, and has the evil reputation of having been the most vicious and harmful medical system ever practised.
In the first third of the nineteenth century:
13. The theory of excitement, a form of Brunonianism, in vogue in Germany.
14. The Italian system of stimulus and contrastimulus, an off shoot from Brunonianism, developed by Basori (1762-1837).
15. Homeopathy, founded by Hahnemann (1755-1843), first promulgated in 1810, and still surviving as an example of ancient medical beliefs.
16. Broussaisism, so-called "physiological medicine," founded by Broussais (1772-1838) of France, and in vogue for a decade or two from about 1816, which looked upon gastro-enteric inflammation and irritation as the cause of diseases in general.
Thus the history of internal medicine shows a succession of ephemeral systems and theories from Hippocrates down to about the second quarter of the nineteenth century. In the various systems that developed a few factors stand out prominently around which the theories centered. Thus, the fundamental distinction between spirit and matter, or between living and non-living matter, furnished grounds for basing medical philosophies on the spiritual (or vitalistic) principle or on material factors, respectively. Among the materialistic medical systems, some (the "solidistic" theories) were grounded on the solid structures of the body, others ("humoral" systems) on the body fluids; some ascribed vital processes and derangements to chemical activities, others to the physical, mechanical or dynamic activities of the body structures ("mechanistic" theories).
Although centuries after the end of the middle ages in other respects, the second quarter of the nineteenth century may be fixed upon as the approximate termination of the medieval period of internal medicine, since down to that time the dominant tone of medical thought was about the same as it had been throughout the middle ages, or indeed since the time of Hippocrates. There had of course been some advance since Hippocrates, as in the differentiation of various diseases and the discovery and introduction of remedial agents; moreover, the development of scientific anatomy, physiology and chemistry could hardly fail to have had a salutary influence on medicine. Yet the dominant conceptions in pathology and etiology and the rationale of therapeutic practise were practically not more advanced, more rational, or more efficient a hundred years ago than they were two thousand ​years ago. In the various systems that were propounded by the leaders in medicine, principles that were more or less true in a limited field were taken to be of universal applicability. Medical science and art can not, however, be reduced to one or a few general causes, laws and formulas; each disease is a problem by itself, which must be worked out in all its aspects independently of other diseases. Hence the intellectual labors of a host of ingenious and talented thinkers for ages were wholly wasted, and effected no real advance in internal medicine, because they employed fallacious methods of thought.
Modern Medicine.—In the past seven or eight decades a radical transformation has taken place in internal medicine, pathology and therapeutics, which has put these subjects on the same high plane as any of the modern departments of science. There was no sharp dividing line of time between the old and the modern periods, but the new medicine developed gradually simultaneously with the decline of the old. The difference between the two depends on radical differences in logical method; modern medicine is developed by inductive, objective, empirical methods of attaining knowledge, the old doctrines were a product of theorizing and speculation. The evolution of modern scientific medicine has taken place along several independent lines of development.
The first branch of internal medicine to be elaborated on sound foundations was pathologic anatomy, its objective and obvious data making it facile of study. The pioneer in this branch was Morgagni (1682-1772) of Italy, whose epochal work on this subject appeared in 1761, when its author was 79 years of age. Other early workers in this field were John Hunter (1728-1793) of London and Bichat (1771-1802) of Paris. Bichat was followed by a brilliant group of French investigators during the first few decades of the nineteenth century, among the most eminent of which were Corvisart (1755-1821), Laënnec (1781-1826), Dupuytren (1777-1835), Andral (1797-1876), and Louis (1787-1872). The work of this group for a long time gave medicine a dominant pathologic-anatomical tone, especially in France.
The physical examination of patients by modern methods had its beginning in the introduction of percussion by Auenbrugger (1722—1809) of Austria. His method was published in 1761, but attracted no attention until it was revived by Corvisart (1755-1821) of France, who in 1808 published a translation of Auenbrugger's contribution which effectively brought it into use. The sister art of auscultation was introduced in 1819 by Corvisart's pupil Laënnec (1781-1826). Since that time there have been gradually developed the multitude of methods, physical, instrumental, chemical, microscopic and biologic, at present in daily use in the examination of the sick.
In the differentiation, clinical study and practical treatment of ​the various diseases much advance was made after the first quarter of the last century. The British physicians made especially valuable and numerous contributions in this field, displaying a practical and clinical bent contrasting with the dominant anatomical tone of the contemporary French school. In the last decade of the eighteenth century Edward Jenner (1749-1823) had introduced vaccination against smallpox. The second quarter of the nineteenth century was one of active development and many important contributions were made by the British clinicians, typically and brilliantly begun by Richard Bright (1789-1858), of London, who in 1827 elucidated the subject of renal diseases ("Bright's disease"). Among others eminent in this period were William Stokes (1804-1878) and Robert James Graves (1797-1853), of Dublin; and John Hughes Bennett (1812-1875), of Edinburgh, who was influential in bringing about the disuse of bleeding. The conceptions of continued fevers, which had previously always been vague and confused, were immensely clarified about this time by the differentiation of typhus and typhoid fevers as distinct diseases; this result was largely brought about by a contribution in 1837 by an American, W. W. Gerhard (1809-1872), of Philadelphia. Anesthesia with nitrous oxide was introduced in 1844 by Horace Wells, a dentist of Hartford, Conn.; with ether in 1846 by another dentist, W. T. G. Morton of Boston; and with chloroform in 1847 by Sir James Young Simpson, of Edinburgh.
About the middle of the last century the medical doctrines of the French school were introduced into Vienna by Rokitansky (18041878), who with Joseph Skoda (1805-1881) and others were pioneers in that development of scientific medicine in Austria and Germany which has attained such eminence. The identification of the cells of plants and animals by Schleiden and Schwann about 1838 opened the way to new conceptions of vital processes, and in 1858 Rudolph Virchow (1821-1902) presented his epochal doctrine of cellular pathology.
The discovery of the pathogenic role of bacteria and the development of bacteriologic science has been one of the most illuminating developments in the whole history of medicine, elucidating, as it has, the pathology of the large and important group of infectious diseases and vastly increasing the efficiency of medical and surgical treatment. Following earlier scattered discoveries, the great foundations of bacteriology were established by Louis Pasteur (1822-1895), of France, beginning during the fifties of the last century. The introduction of improved methods of research by Robert Koch (1843-1910), of Germany, about 1882, gave the science a vast impetus. The principal application of bacteriologic science has yielded incalculable benefits to humanity, as in the introduction of antisepsis by Sir Joseph Lister (1827-) during the sixties of the nineteenth century, of the ​specific serum and vaccine treatment of certain diseases, of prophylactic measures, and of the specific methods of diagnosis.
The tremendous and revolutionary advance made by medicine in the past few decades is obvious to the most superficial view. It is quite apparent that internal medicine has just been having its Renaissance, even within the lifetime of men now living having passed through that stage of development that other departments of human thought and activity passed through centuries ago. We have only just emerged from the middle ages in medicine. The movement is still in unabated activity. The final goal is far from having yet been reached, and there are vast fields in medicine yet to be cultivated before the one-sided and partial developments of the past will be amplified into a more symmetrical and perfect form. With medical research and progress continuing at the present rate, the outlook is rich with promise for the future development of medicine and added benefits for mankind.
In looking over its history we can distinguish the operation of two contrary tendencies or methods of thought which have controlled the evolution of medicine. These two principles mark off the history of medicine into two epochs, the speculative and the scientific, of a distinctiveness more fundamental than the ordinary division into such periods as the ancient, Arabian and medieval. These two factors are: (1) the subjective, deductive, a priori or speculative, and (2) the objective, inductive, a posteriori, empirical or scientific, methods of attaining knowledge.
The subjective or speculative method is the one that prevailed throughout medical history down to the modern era. It is far the more attractive and has much the stronger hold on human nature; it is the primitive and natural method of the untrained mind. It is easy and pleasant to construct complete schemes of the universe by introspection. Scientific investigation is tedious and laborious, and leaves many gaps in knowledge. There is a demand in human nature for certainty, and completeness, and finality in knowledge. Our patients, for example, demand this in our diagnoses and prognoses. The mind is impatient with the unknown, and is prone to fill up the blanks in knowledge by premature generalizations and assumptions.
The objective or empirical method of gaining knowledge is the one that characterizes modern science. Rigidly suppressing preconceived notions and bias, this method proceeds by painstaking observation and investigation to collect an adequate mass of objective data as a prerequisite to generalization. This method is not natural to human nature, but is a product of culture. In the history of mankind, it was ages before, in the Renaissance, it came to dominate the best thought; and among the mass of people at the present time it is only a cultured few who are thoroughly imbued with its spirit.
​The utter futility of the speculative method as a means of attaining effective knowledge is completely demonstrated by the stagnation and inefficiency of medicine under its influence for thousands of years. The only sure and effective way of gaining knowledge is the empirical method, by patient observation and investigation, the tardy adoption of which was the sole means by which internal medicine has been revolutionized and vivified. The keynote of the true method was struck by John Hunter in his advice to Jenner when the latter was beginning to ponder on the subject of vaccination, "Do not think; investigate." The whole history of medicine is an imposing demonstration of the futility of theorizing and the utility of scientific investigation. This lesson should come home to every one of us, and indicate the only mental attitude we can safely assume. We should formulate our judgments only by the objective and empirical route. We should avoid dogmatism, premature theorizing, and generalization from insufficient data. We should frankly admit our ignorance, and not deceive ourselves or others by unfounded assumptions. We should practise a healthy skepticism, and carefully scrutinize the information offered us. No authority is too eminent, no traditions too ancient, to be exempt from criticism. The vast amounts of chaff in our professional literature need to be carefully sifted for the few kernels of truth; while to a far greater extent the ready acceptance of the interested representations of commercial establishments is a mark of naive simplicity and easy credulity. Always as the test of verity should be demanded the evidence of and agreement with an ample body of objective data. These considerations may seem trite, yet experience constantly demonstrates the necessity for their vigilant observance.
It is disquieting to reflect on the inefficiency and even harmfulness of much of the medical practise of the past. Yet our predecessors were men of sincerity and high ideals, and had the trust and confidence of the mass of the people. The therapeutic successes of the past must be construed mainly as an exemplification of the potency and action of psychotherapy.
Although the scientific method imposes rigorous criteria for the acceptance of doctrines, yet truths so established rest on a firm and abiding basis. For this reason we can feel confidence in the validity and permanency of such of our present medical theory and practise as has a thorough scientific basis. We have good reason to feel that at last we have attained some degree of finality in many of our doctrines; that the medicine of to-day is radically different from the ephemeral systems of the past and wherever thoroughly grounded on a scientific foundation will stand for all time.
If it be true that medicine has only just emerged from the middle ages, some medieval error must still persist in our doctrines and ​practise, which it behooves us to clear away. A keen criticism could doubtless disclose much of ancient error and fetishism in our materia medica and therapeutics and our pathological conceptions of obscure diseases. The entire profession does not even yet willingly and unreservedly accept the scientific element in internal medicine. The necessity and duty of thoroughly scientific methods in surgical and obstetrical practise is generally appreciated; but the obligation for equally thorough and scientific diagnosis and treatment in internal medicine is not so generally recognized. On the contrary, there is rather prevalent a spirit of disparagement and deprecation of what are called scientific methods, and insinuations are frequently made that they are not practical or useful. This spirit possibly arises not so much from frank conviction as from indisposition to keep fully abreast of the rapid developments in medicine, and a latent jealousy of those more advanced. That scientific methods in medicine (aside from those purely academic) are unpractical and useless is diametrically contrary to the reality; since it is such methods alone that have gained, and are gaining, and can gain for medicine all the real efficiency that it possesses. It is to me inconceivable that any methods in rational medicine can be other than truly scientific in their essence; sectarians, and laymen, and quacks can practise non-scientific medicine, but not true physicians. Our patients are entitled to the best possible service available, whatever be the character of any procedure that may be of use; and nothing short of this best is good enough for either the patient or the conscientious practitioner.
If a trained medical profession has only just found enlightenment, it can not be expected that the great untrained public will yet have emerged from medieval darkness in matters medical. The general public at the present time is actuated by the identical speculative spirit that for ages and until recently exercised its blighting control over the medical profession. A realization of this fact explains much that now seems anomalous and vexatious, and points the way of future betterment.
In many quarters the attitude of the public toward the medical profession is one of misunderstanding, distrust and antagonism. Fads and sects, like homeopathy, osteopathy and christian science, have a large and influential following, including the most intelligent and respectable members of the community. The hold which these (to us) irrational beliefs have on the public seems amazing and exasperating; yet the profession has only recently been emancipated from systems of precisely the same character—too recently for the public yet to have followed. Our customary attitude toward sectarianism is one of ridicule and denunciation; an attitude which produces infinitesimal results. These popular beliefs are not the product of perversity or wickedness, but result from powerful tendencies in human nature—the proneness ​of the mind to speculative thought; and the proper remedy is not vituperation, but education. With the diffusion of medical knowledge among the people—not by hysterical propaganda but by gradual and substantial enlightenment—which seems inevitable now that the profession can exert its influence from an unimpeachable basis, greater mutual sympathy and understanding are bound to come between the public and the profession.
In its rational development internal medicine is the laggard among the medical sciences, having always been centuries behind such branches as surgery and anatomy. This is natural, since the data of the latter are superficial and obvious, while those of internal medicine are deep-seated, obscure and inaccessible, and allow much play for theory or imagination. Moreover, internal medicine lacks the spectacular appeal which is exerted, for example, by surgery. Yet though its data are inaccessible, its problems difficult, its therapeutic possibilities limited, the greater the difficulties the greater is the glory of surmounting them, and it is evident that internal medicine has at last entered upon a career in honor and efficiency second to none.