The proving of drugs affords a twofold advantage. In the first place the proving physician sharpens his power of observation and accustoms himself to notice the minutest symptoms of disease, every one of which ought to be of sufficient importance to the physician to embody it in his record of the case; and, in the second place, by proving the drug upon himself, he acquires a true perception of its curative powers, which, in his person, manifest themselves unbiassed and unmixed with the heterogeneous influences of other medicinal agents. How different is the homoeopathic materia medica from that of the old school, which is a mere assemblage of impure and uncertain effects of drugs as observed at the sick-bed, and not of one drug at a time, but every drug being administered in company with a variety of other drugs, and the whole being adorned with strange speculative views about the chemical, dynamic, clinical, mechanical and specific virtues of a drug. No sort of reliance can be placed upon such statements. If the materia medica of the old school is to be used with confidence, it must be constructed like our own, and, in that case, it will be merged in homoeopathy; for the homoeopathic law is confirmed in all cases where the pathogenetic effects of our drugs and the curative results which have been obtained by means of them, are compared with one another.

The investigation of the symptoms of a disease is the third fundamental rule in homoeopathy. The importance of that investigation has been urged by Hahnemann with great force, because the proper selection of the remedial agent, and consequently the success of the treatment depend upon it. He recommends that the symptoms of the disease be noted with the same care- and completeness as were the symptoms of the drug, and that the former be counterbalanced and effaced by the latter. This proposition has been attacked on all sides, and has been strangely misapprehended. It has been supposed, for instance, that Hahnemann neglected to take cognizance of the exciting cause, the causa occasionalis of the disease. The opponents of homoeopathy have frequently charged that neglect upon our practice; but unjustly so, for every homoeopathic practitioner knows, that, in many cases, the proper selection of the remedial agent depends exclusively upon a knowledge of that cause, inasmuch as the symptoms of two entirely different diseases may apparently be alike, and the difference can only be recognised by tracing the symptoms to the exciting cause. We will illustrate this by a few examples :

We know from experience that Arnica is most use- ful in diseases resulting from blows, contusions, wounds, strains, etc.-A man who has been drenched to the skin is frequently attacked with a variety of symptoms corresponding to those of Rhus tox., which it would be difficult to cure if the exciting cause were not known.- What physician would not give Cocculus against a febrile state characterized by flushed cheeKs and nightly sleeplessness, if he knew that home-sickness was the exciting cause? - Fright occasions a great many symptoms for which we have specific remedies in our materia medica; Ignatia for grief, Aconite for a vexed and irritable mood, Opium for fear.- Ignatia is a sure specific for symptoms resulting from grief and chagrin; Chamomilla, on the contrary, is a specific for the consequences of chagrin, when accompanied with anger and vehemence. - It would be a long and difficult business to cure a derangement of the stomach, if the physician did not know the exciting cause; but it will be readily removed by a dose of Pulsatilla, if it had been occasioned by fat food, especially pork; by Arsenic, if it owes its existence to a cold in the stomach, to eating cold fruit, etc. - Physical and mental weakness resulting from blood-letting, hemorrhage, waking, night-sweats, onanism, venereal excesses, etc., finds a specific in China, provided the weakness is the principal suffering, and not a mere symptom of a more general and deeper-seated disease. - Diseases resulting from want of exercise, yield to Nux; but could they be cured as readily if the exciting cause were not known? - Dulcamara is the specific for diarrhoea, with or without colic, occasioned by cold, and sometimes accompanied with swelling of the glands. - A homoeopathic physician who is acquainted with the pure effects of Chamomilla, Mercurius, Sulphur, China, Valeriana, Iodine, etc., will never prescribe those remedies without inquiring in the first place whether the symptoms have not been occasioned by the excessive use of those substances, in which case he would administer suitable antidotes. - Would it be easy to cure the sufferings resulting from the excessive use of ardent spirits, if the exciting cause were not known? It would not, if the physician were ignorant of the exciting cause, and of the pure effects of Nux vom., which correspond to the symptoms occasioned by spirituous drinks.

These examples, which might be multiplied by many more, will suffice to show the importance of investigating the causa occasionalis, and will at the same time silence the accusation of our opponents, that the investigation of the causa occasionalis is neglected by practitioners of our school.

Homoeopathic physicians know just as well as the physicians of the old school, that the visible symptoms of a disease are accompanied with changes in the internal organism, which are considered the essence of the disease by allopathic physicians. Homoeopathic physicians, however, do not believe, that we can have a sufficiently clear perception of those changes to base upon them our principles of cure. Homoeopathic practitioners are guided by the visible symptoms in selecting the appropriate remedial agent; without denying the existence of the first cause of the disease they observe with especial care the symptoms of the disease, and consider them sufficient indications of cure. Homoeopathy accepts the symptoms which we are now able to obtain by means of auscultation and percussion, and which aid us in establishing a correct diagnosis; by means of auscultation and percussion, and even by the investigation of the pathological changes, we obtain a more accurate knowledge of the internal phenomena of the disease, and avail ourselves of that knowledge wherever we can improve and complete, by its means, the application of our therapeutic law. In order to apply this law to the pathological phenomena we shall have, in the first place, to ascertain what drugs will produce similar phenomena in the healthy organism. We need not to mind the reproach of curing merely by symptoms; years of experience have sufficiently shown that a disease is cured when its symptoms cease to exist.

The investigation of the symptoms of the disease requires to be made with the greatest care and correctness; not even the slightest symptom ought to be omitted. On taking such a record of the symptoms, every case of disease will necessarily appear as a distinct, individual case which has never occurred before. This explains why Hahnemann denied the validity of all nosological classifications, as a means of cure, and admitted their use only for the purpose of collecting the symptoms under one general denomination. In the present work we have retained the pathological denominations, because we are persuaded that they facilitate the study of homoeopathy to the beginner; we have indicated, however, with as much care as we were able, the specific remedies for the various groups of symptoms occurring in a disease; and we expect, therefore, that we be not blamed for having made this arrangement.

Hahnemann insisted upon every record being taken in writing, lest symptoms should be forgotten by the physician. An examination instituted by a homoeopathic physician is much more minute than an examination instituted by an allopath; this one neglects to take cognizance of various exciting causes which require the administration of peculiar specifics in homoeopathic practice.

"§ 83. This examination of a particular case of disease, (says Hahnemann,*) with the intent of presenting it in its formal state and individuality, only demands, on the part of the physician, an unprejudiced mind, sound understanding, attention and fidelity in observing and tracing the image of the disease. I will content "myself, in the present instance, with merely explaining the general principles of the course that is to be pursued, leaving it to the physician to select those remedies which are applicable to each particular case.

"§ 84. The patient details his sufferings; the persons who are about him relate what he has complained of, how he has behaved himself, and all that they have remarked in him. The physician sees, hears, and observes, with his other senses, whatever there is changed or extraordinary in the patient. He writes all this down in the very words which the latter, and the persons around him, made use of. He permits them to continue speaking to the end without interruption,* except where they wander into useless digressions, taking care to exhort them, at the commencement, to speak slowly, that he may be enabled to follow them in taking down whatever he deems necessary.

"* Every interruption breaks the chain of ideas of the person who speaks, and things do not afterwards return to his memory in the same shape he would at first have described them.