This is another aid that has been found necessary to facilitate the selection of the indicated remedy. It is a useful appendage to the homoeopathic Materia Medica, by means, of which we can readily discover almost any recorded symptom of any proven drug. The secret of successful use of the "Repertory" is to get thoroughly acquainted with any one of the different repertories by constant reference to it, thus familiarizing oneself with its peculiar arrangement. The most helpful of them all, but the one requiring, also, most patient study, is Boeninghausen's "Therapeutic Pocket Book". Its arrangement is based on a practical analysis of symptoms into their component elements of location, sensation and conditions. (See Chapter V (Interpretation Of Drug Pathogenesis)).

How to learn Drug Pathogenesy and acquire a working knowledge of the homoeopathic Materia Medica has occupied the students of Homoeopathy from the beginning of the school. Unquestionably, the proving of a drug is the truly natural and most effective method of getting a knowledge of its action, and every physician and student should undertake such practical study as at least part of his study of materia medica. It is the true, modern, scientific method by appeal to nature herself. In the absence of this, and as a further aid, the study of original provings, and of records of poisonings, will go far to give a good general outline of the action of a drug. This should be followed by the carefill and repeated reading of the recorded symptomatology, noting the parts especially involved, character of the symptoms, the conditions under which they occur, and the concomitants connected with each symptom. In this way the peculiar and characteristic symptoms and conditions will appear, which will be the guiding symptoms in practice. These characteristics, so-called key-notes, of the different remedies, must be committed to memory, they form the stock in trade of the homoeopathic prescriber, and will lead to the further and more detailed and comparative study of the remedies.

For further study, consult Hughes, "Sources of the Homoeopathic Materia Medica," in his work on Pharmacodynamics; also published separately by Leath & Boss, London.

Dr. John W. Hay ward: "How to Learn Drug Pathogenesy," with discussion, in the Journal of the British Homoeopathic Society, January, 1895.

The following classical papers should also be consulted:

Constantine Hering: "How the Materia Medica should be Learnt," in British Journal of Homoeopathy, Vol. II.

Dr. Meyer, one of Hahnemann's immediate disciples, on the same subject, in North American Journal of Homoeopathy, Vol. II.

Dr. Pope, in Monthly Homoeopathic Review, VIII, and Vol. XXV.

Dr. H. R. Madden, in same journal, Vol. XIV.

Dr. R. Hughes, in same journal, Vol. XXIII, and in Hahne-mannian Monthly, Vol. XXIX.

Dr. C. Wesselhoeft in N. E. Medical Gazette, Vol. XXII. Dr. Joseph C. Guernsey, in Hahnemannian Monthly, Vol. XXIX. American Institute Report for 1894, Materia Medica Section; opinions of thirty-one members. Edited by Dr. Frank Kraft.