MEDICINE [HISTORY. a corresponding degree of opposition. The most important adherent to Brown s system was Rasori (1763-1837), who taught it as professor at Pavia, but afterwards substituted his own system of centra-stimulus. The theoretical differ ences 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, a German, professor at Pavia, afterwards of Vienna, the author of an e-ncyclopredic work on medicine now forgotten; embraced the Brunonian system, though he afterwards introduced some modifications, and trans planted 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. Girtanner first began to spread the new ideas (though giving them out as his own), but Weikard was the first avowed advocate of the system. Roschlaub (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 Hush, 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 Broussais, who, though not rightly classed with the system-makers, since his conclusions were partly based upon anatomical investigation, resembled them in his at tempt 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 philo sophy and the moral sciences had fostered a love of abstract speculation ; and some sort of cosmical or general system was thought indispensable in every depart ment of special science. Hence another generation had to pass away before Germany found herself on the level, in scientific investigation, of France and England. Bafore 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 Hahne- mann (see HOMEOPATHY). 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 for ward views respecting the causes of disease which hardly bear to be seriously stated. All chronic maladies result either from three diseases psora (the itch), syphilis, or sycosis (a skin disease), or else are maladies produced by medicines. Seven-eighths of ail chronic diseases are pro duced by itch driven inwards. 1 (It is fair to say that 1 The itcli 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. these views were published in one of his later works.) In treatment of disease Hahnemann rejected entirely the notion of a vis medicatrix nature, and was guided by his well-known principle " 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 indica tion 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. Hahnemann s doctrines met with much opposition on the part of the medical pro fession, and he was hence led to state his case to the "lay" public as a sort of court of appeal; and thus matters of science were made the theme of much popular controversy. This expedient, in which Hahnemann had been in a small degree anticipated by Brown, contributed largely to the success of his system. The appeal flattered a prevalent belief in the right of private judgement, even in technical and learned subjects. Hahnemann was thus able to take up the position (and not without justification) of a victim of professional prejudice. The anomalous position into which professional scorn and extra-professional popularity brought him produced a distinct deterioration in the character of his work. In his second period he developed the extraordinary theory of " potentiality " or dynarniza- tion, namely, that medicines gained in strength by being diluted, if the dilution was accompanied by shaking or pounding, which was supposed to " potentialize" or in crease the potency of the medicine. On this extraordi nary principle Hahnemann ordered his original tinctures to be reduced in strength to one-fiftieth ; these first dilu tions 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." It is hardly necessary to point out that even the lower dilations involve quantities which no analysis can weigh, measure, or even recognize. The still greater eccentricities of Hahnemann s later works need not be recounted. 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 drug?, often hetero geneous 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 ISth Century. In looking back on the repeated attempts in the 18th century to construct
a universal system of medicine, it is impossible not to