In the collection of provings of rhus toxicodendron made by Samuel Hahnemann, and published in Vol. II. of the Materia Medica Pura, the number of symptoms relating to the eye and its neighborhood is so large as to lead to the supposition that, if the theory of homeopathy be a correct one, this drug should prove of special value in the treatment of diseases of the visual organs. Never did an hypothesis receive better support when reduced to practice; and if the efficacy of the law of _similia similibus curentur_ were compelled to rest upon a single test to demonstrate its truth, few better selections could be made than that of rhus tox. in the department of ophthalmology. Many of the symptoms contained in the Materia Medica Pura are indefinite, and the great majority of them point to apparently superficial diseases, but when we consider the fact that at the time these provings were made the science of ophthalmology, as understood at the present day, actually had no existence, that the principle of the ophthalmoscope had not yet been discovered, and that the methods of precision in the examination and diagnosis of diseases of the eye now available were at that time unknown, this is little to be wondered at. And we are compelled to admire the industry and energy of the men, some of them of our own day and generation, whose tireless labor has sifted and arranged the numerous symptoms of this and other drugs and indicated the method of their proper application to the various pathological processes. When the New York Ophthalmic Hospital was placed in charge of the adherents of the homeopathic school, they were confronted by the fact that no definite materia medica of diseases of the eye and ear, as such, was in existence, and in order to ascertain the remedy for a given case of disease they were obliged to take the conditions throughout the body, and by comparing these with the general materia medica find a suitable drug for the totality of the symptoms. Had they been content with simply curing their cases in this routine way little would have been gained, but they made it a rule to take down the special eye or ear symptoms in each case with great care, and when a drug had cured a certain case of disease the eye or ear symptoms which had disappeared under its use were carefully noted. With a multiplicity of cases, and a systematic verification of symptoms, a valuable special materia medica of these diseases was compiled, and the curative properties of drugs in the various pathological entities of the eye and ear were definitely demonstrated and their characteristic symptoms for each disease mapped out.