Like affections are cured by their similars, expresses the law for drug selection in all curable forms of disease. By its application, the curative remedy is found in curable cases; and in incurable cases, the same law usually points to a remedy that will act palliatively in most conditions. By Law of Cure is meant the definite path along which a drug force moves to cure a diseased condition. This law forms the basis of Homoeopathy [from the Greek words homiios and pathos, meaning similar affections], the therapeutic method that applies the principle that any drug which is capable of producing symptoms of disease in the healthy will remove similar symptoms, and thus cure the disease when found in the sick.

* There exists a misconception concerning the phraseology employed by Hahnemann in the expression of the Law of Similars. Dr. R. E. Dudgeon, the recognized authority concerning the works of Hahnemann, writes in the appendix to his translation of the Organon, "Hahnemann always wrote the formula Similia Similibus Curentur, thereby giving an imperative or mandatory turn to the phrase". The translation must evidently be "Let likes be treated by likes". "Durch Beobachtung, Nuchdenken und Erfahrung fand ich, dass im Gegentheile von letztern [Erleichterungsmittel und Palliative durch die Curart contraria contrariis] die wahre, richtige, beste Heilung zu findensei in dem Satze Similia Similibus Curentur. Wilhle, um, sanft, schnell, gerwiss und dauerhafl zu heilen, in jedem Krankheilsfalle eine Argnei, welche ein aehnliches Leiden fur sich erregen kann, als sie heilen soil!" Nevertheless, Similia Similibus Curantur has been almost universally adopted by the homoeopathic school, and the belief and conviction have been unconsciously expressed thereby that it is a law of nature - S. S. Curantur - Likes are cured by likes; rather than a rule of art, S. S. Curentur - Let likes be treated by likes.

The first promulgation of this principle was made by Hahnemann in 1796, in an essay published in Hufeland's Journal, entitled "On a new principle for ascertaining the curative properties of drugs". In this essay Hahnemann formulated his conclusions thus: "Every powerful medicinal substance produces in the human body a peculiar kind of disease, the more powerful the medicine, the more peculiar, marked and violent the disease. We should imitate nature, which sometimes cures a chronic disease by superadding another and employ in the disease we wish to cure that medicine which is able to produce another very similar artificial disease, and the former will be cured - Similia Similibus".

This was six years after his first experiments with Cinchona bark, which was the first drug experimented with and which gave striking evidences of the similarity between the effects it is capable of producing, and those for which it had ever been employed, and which was the beginning of a rational, scientific, Materia Medica, and of a scientific therapeutics based thereon. The most characteristic feature about the development of Homoeopathy is the strict observance of the inductive method of research that Hahnemann adopted. Careful experiments were instituted, all preconceived theories were ostracized, and the results and rigid deduction from them were not published until years had elapsed in which to verify all the statements.

The development of the homoeopathic principle began in the mind of Hahnemann with his experiments with Cinchona, which in turn led him to other experiments with other drugs and patient search of recorded action and uses of drugs throughout the medical literature. His first suggestions fell unheeded by the profession; but he continued his experiments, and nine years later published a work in Latin "On the Positive Effects of Medicines," and at the same time declared the principle of Similars as a law of general application. Five years more of further reflection and experiment enabled him to perfect his system and embody its principles in his great book, the "Organon of Rational Medicine". The following year, while a teacher at the University of Leipsic, he published volume I of his "Materia Medica Pura," containing original provings made by himself and members of his family, and assisted later by some enthusiastic disciples that gathered around him at the University; and in 1821 he published the final sixth volume, containing the positive effects of sixty-four medicines. With the publication of these two great works, Hahnemann provided both the theoretical and practical requirements of Homoeopathy as a distinct method of therapeutics. He was the first to apply the inductive method of research to therapeutics. He says, in the preface to the second edition of the Organon, published in 1818: " The true healing art is in its nature a pure science of experience, and can and must rest on clear facts and on the sensible phenomena pertaining to their sphere of action. Its subjects can only be derived from pure experience and observation, and it dares not take a single step out of the sphere of pure, well-observed experience and experiment". And, again, " Every one of its conclusions about the actual must always be based on sensible perceptions, facts and experiences, if it would elicit the truth".