Hahnemann, CHRISTIAN FRIEDRICH SAMUEL, the founder of the homeopathic method of treatment (see HOMEOPATHY), was born at Meissen, in Saxony, April 10, 1755. Educated at the grammar-school of Meissen, he entered the university of Leipzig at the age of twenty; and it was by teaching and translating books written in English, French, Italian, Latin, Greek, Hebrew, and Arabic that he supported himself while at the university. The reputation he had made for himself as a scholar while at Meissen procured for him a free admission to the university classes. From Leipzig he proceeded to Vienna for clinical study, where he was the favourite pupil of Von Quarini, physician to the Emperor Joseph. He then passed two years as physician and librarian to a nobleman residing in Transylvania, after which he entered and, in 1779, graduated at the university of Erlangen. During the following ten years he practised medicine and held several public appointments in Dresden and elsewhere, and then settled in a small village near Leipzig. His observation and practice had so fully convinced him, not only of the uselessness, but also of the injurious character of the prevailing methods of treatment, that he now abandoned all practice and devoted himself to chemical research and the translation into German of foreign scientific books. Of these, Cullen's Materia Medica was one. Feeling dissatisfied with his author's explanation of the modus operandi of bark in curing ague, it occurred to him to endeavour to find out what kind of action this drug had on persons in health. He accordingly took considerable doses of bark himself, when he observed that they caused some of the symptoms he had noted as being characteristic of ague in Transylvania. This experiment led to his interpreting the curative power of bark in this fever by the hypothesis that it 'overpowers and suppresses the intermittent fever by exciting a fever of its own of short duration.' This appears in one of his notes in his translation of Cullen. Thus, as Ameke remarks, 'he started with the idea of aiding the recuperative power by a medicinal excitant acting directly on the part affected.'
His experiment also convinced him that it was by ascertaining the effects a drug produced on healthy persons that its mode of action could most surely be ascertained. He therefore commenced a research into the records of medicine, examining the reports of cases of poisoning by individual drugs, and made experiments with other drugs upon himself and his friends. He then studied all the cases of cure by these same drugs that he could find. In these investigations he occupied six years. They proved to him that, whatever might be the truth of the theory the bark experiment had suggested, the fact was that in all instances the medicine which had cured produced a very similar condition in healthy persons to that it had relieved. This conclusion he published in an essay in Hufeland's Journal in 1796, having the title of 'A New Principle for ascertaining the Curative Properties of Drugs.' It is in this essay that the principle or rule of similia similibuscurentur is first put forward by him, not as a theory but as a fact. His views at once met with vehement opposition. His denun- ciation of blood-letting and other violent modes of treatment aroused the animosity of physicians, while the very small doses of medicine which alone were needed according to his new method, provoked the apothecaries, whose trade interests were threatened. They refused to dispense his prescriptions, and he accordingly gave his medicines to his patients without any charge. For a physician to dispense his own medicine was an infringement of the rights and privileges which German law had conferred upon the apothecaries, and hence he was prosecuted in every town in which he attempted to settle from 1798 until 1810, when he returned to Leipzig. Two years afterwards he was appointed a privat-docent—or extra-academical lecturer—of the university. The thesis he defended before the Faculty, when a candidate for this position, has been described as 'remarkable for its display of extensive reading in the ancient authors, and not only those more immediately connected with his own professional pursuits, but also in the classical writers of antiquity.' At Leipzig he remained, teaching and developing his system of medicine to an ever-increasing band of enthusiastic disciples, and practising his profession uninfluenced by constantly recurring attacks from his professional neighbours until 1821, when a successful prosecution by the apothecaries for dispensing his own medicines drove him out of Leipzig. Under the protection of the Duke of Anhalt-Köthen he retired to Köthen, where he became a centre of attraction to numerous invalids in all parts of the world. His wife dying in 1831, in 1835 he married a French lady, who induced him to remove to Paris, where he resided and practised until his death, 2d July 1843.
Hahnemann is also known as one of the earliest advocates of hygiene. His book entitled The Friend of Health, published in 1792, proves him to have been very far in advance of his time on what is now called preventive medicine. Equally so was he in the treatment of the insane. His account of his successful treatment of a certain Hanoverian statesman, who, becoming maniacal, was placed under his care, shows that in 1794 he had adopted those principles of non-restraint and kindness in dealing with the insane which in later years were advocated by Pinel in Paris and Conolly in England. He was also the author of several valuable papers on chemistry in Crell's Annalen der Chemie—the first German periodical devoted to that science. A statue of Hahnemann was erected in Leipzig in 1851. See his Life by Albrecht (2d ed. Leip. 1875).