It is now more than fifty years since homoeopathy was discovered by the profound and learned Dr. Hahnemann. Its claims and merits are now universally appreciated, and in spite of the intrigues and invectives of its opponents, it has succeeded in gaining the rank of an acknowledged science. It owes its triumph to the fact that the principles of homoeopathy are generalizations established in the eternal and immutable household of nature. During the first twenty years of his discovery, Hahnemann was alone in cultivating and perfecting it; but after that period he formed disciples; physicians from the old school,, who at first considered homoeopathy a mere creation of the fancy, became converts to the new doctrine, and, at the present moment, it is triumphantly practised in every civilized country, and not only spreads farther and farther, but its intrinsic value is likewise being constantly enhanced by new discoveries. This success could only be accomplished by a mode of cure which is derived from the laws of nature, and is confirmed every day by the results of experience. But what will be the influence and extent of homoeopathy when its practitioners shall have increased by thousands, and shall devote all their energies to the development of their art; heedful of the warning of their master, that no created spirit can penetrate to the causative principles of nature without substituting in their stead speculative and hypothetical explanations and opinions and receding more and more from the paths of nature? We may certainly hope, without being sanguine, that after the next fifty years, homoeopathy will be far 2 ahead of any other system of cure. Be it remembered, however, that, in order to attain such brilliant results, all homoeopathic practitioners ought to devote themselves to calm inquiry and rigid observation, and that their efforts in the great cause ought never to slacken.

However interesting it might be to our readers to glance in this place over a detailed account of the mode in which Hahnemann gradually arrived at the discovery and realization of his system, yet we prefer omitting the relation of facts with which our readers are abundantly familiar, and confine ourselves to stating the fundamental principles of homoeopathy; these form a complete system of general therapeutics, and a correct knowledge of those principles is essential to the proper understanding and appreciation of the special principles of our treatment of disease.

The fundamental principle of homoeopathy is expressed in these words : " Similia similibus curantur," which means, that only such remedies are capable of effecting a permanent and real cure as affect the healthy organism in a manner similar to the natural disease. This fundamental principle of cure was discovered by Hahnemann while he translated Cullen's Materia Medica (Leipsic, 1790), where his attention was arrested by the statements about the febrifuge power of Cinchona. Upon proving this drug on healthy persons, a state similar to fever and ague was realized in the provers, beside many other symptoms which had never been mentioned by any writer before. From this fact Hahnemann inferred what was afterwards confirmed as a great truth, that medicines are only in so far capable of curing disease as they realize in a healthy person a morbid state similar to the natural disturbance of the organism. Led by his experience, Hahnemann established the following rule for the further development of his system :

Prove the drugs upon healthy persons, in order to find out what systems and organs are principally affected by them and what are the symptoms characterizing that affection. It is true that the necessity of such provings had been perceived by single physicians, and that partial provings have been instituted before Hahnemann; but they were never carried on systematically with a view of obtaining a correct knowledge of the curative powers of drugs and applying them to the treatment of disease according to a fixed general principle. The road of pure experimentation was soon abandoned by those physicians as too tedious and too little productive in brilliant results; their prejudices were likewise opposed to a systematic proving of drugs, and Hahnemann is therefore the first who has proclaimed and demonstrated the necessity of pure experimentation, who has furnished explicit and abundant rules for the proving of drugs, and who has furnished to the world the brilliant results of his own provings, which are the groundwork of homoeopathy and a beacon-light and model for all homoeopathic practitioners and pure experimenters.

However laborious and painful the road of pure experimentation may be, Hahnemann never dreaded the tortures and sacrifices which he encountered on that road, and, assisted by devoted disciples, he continued his provings and noted the symptoms which he obtained, with the utmost care. Provers of drugs ought to employ the greatest discretion and care in observing the drug-symptoms which they experience during the period of proving; and they ought moreover to observe a rigorous diet during all that time, lest the action of the drug should be impaired and the symptoms should become impure and untrustworthy. In proving, Hahnemann soon discovered that the drugs had a twofold effect, which he designates in his Organon by the terms of primary and secondary, and which had never been observed before by any physician. Without entering upon an explanation of that compound action, which may be found in the Organon and to which we therefore refer, we content ourselves with simply remarking, in this place, that the primary effect of the drug is sometimes seen in disease in the shape of a temporary exacerbation of the original symptoms.

Such an exacerbation, however, is much less frequent than is supposed. Most of the pretended exacerbations which are recorded in our books have been noticed by beginners in homoeopathy, who had too little knowledge of disease and the effects of the remedies to be able to distinguish a natural from a medicinal exacerbation of the symptoms; or Hahnemann himself was carried away by his own enthusiasm, ands,his disciples were either too timid or too ignorant to correct the errors of his judgment; or the exacerbation might have been owing to the excessive magnitude of the dose or the non-homoeopathicity of the remedial agent. We know that exacerbations may exist, but they are less frequent now than they were in the beginning of homoeopathy, when every aggravation of the symptoms was supposed to be owing to the excessive magnitude of the dose. This error has frequently proved injurious to the patient inasmuch as it induced the omission of many things which ought to have been done and which are done by the present practitioners of homoeopathy whose knowledge of the course, chances, transitions, and the general characteristics of disease, is much better than that of their predecessors. It is still more difficult to account for the exacerbation which is said to be produced by the recently-introduced highest potencies.