“similia 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
one-fiftieth; 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of the depletory system had only partially been superseded by the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 Sénac (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 (q.v.), 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 Haën (1704–1776), Anton Störck (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 François Xavier Bichat (1771–1802). The importance in science of Bichat’s classical works, especially of the Anatomie générale, 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 François Joseph Victor Broussais (1772–1838), whose theoretical views, partly founded on those of Brown and partly on the so-called vitalist school of Théophile 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 (gastroentérite). 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
