Not infrequently there arises in the student mind the question as to whether there is any relationship between isopathy and homoeopathy and the same question is often brought up in discussion among physicians. One and all sense that there is something in common possessed by both. Yet there as yet has appeared in print and I have heard in discussion on concise, logical, and acceptable explanation of this similarity. To date, one has to remain content with the rather incomplete and not entirely satisfactory explanation that homoeopathy is the use of the similar antigen; isopathy is the use of the same antigen.
This is not entirely academic and is certainly lacking in finesse. Also it is not entirely correct, for it is incorrect to say that, for sake of illustration, if plumbum is given in a case of lead poisoning on the homoeopathic symptomatic indications, this remedy is at that time according to the isopathic principle. Only, in such a case, if the remedy plumbum were prescribed upon the known fact that lead was the cause of the condition would it be used in accordance with the isopathic principle. Thus, it can be said that a remedy may in a given case be both isopathic and homoeopathic. The criterion is always to be found not in the character of the antigen but in the finding principle used in the selection of the remedy.
The principle of isopathy calls for a search for the disease- producing agent, customarily but not necessarily in the theoretical sense, confined to the use of drugs. This principle has at times been extended to the employment of of psychic and thermal agents but when such has been the case few have discerned the isopathic principle in the background.
The efficacy of this principle depends, in the last analysis, upon assumption that a given antigen will always, under all circumstances, provoke the same response. Our modern researches have demonstrated that this assumption is incorrect. I have elsewhere shown that the response to any antigen is a highly conditioned reaction. We are making only a factual statement when we say that a given antigen has potentiality to evoke in a living human body a vital response and that the way in which that response shall be manifested, as it is to both prover and physician, is by symptoms of various kinds.
It is also just as true a statement to say that, although the symptoms manifested in a given number of experiment will have a great deal in common, each individual will contribute a greater or lesser number of symptoms possessing a dissimilar nature and having little or nothing in common. This question of similarity and dissimilarity of symptomatology is a coefficient of the human organism and not of the remedy. Variations in the response to a given antigen will depend also on such factors as dose, time, repetition, method of administration, etc.
The precise same situation is clearly illustrated in disease; indeed, drug reactions as observed in the conduction of proving is duplicated in practical medicine. Considering a given bacterial organism, such as the tubercle bacillus, as the antigen, let us enumerate a few of the modes that the human body has of manifesting a reaction to this single antigen. Some of the most common are the pulmonary type, the osseous type, the glandular type. Of these three main types any encyclopedia of medicine will list a large number of variations-stages of the same type, combinations of two or ore types and a host of complications of any one of the types.
This diversity, it is to be remembered, is a coefficient of the body, for in every case the antigen is the same. Now it is important to remember in this connection that isopathy never considers the diversity in the body reaction to a given antigen. Homoeopathy, on the other hand, emphasizes this diversity.
It should be already apparent that the two principles of therapeutics pursue different methods in the selection of the indicated remedy. The one, isopathy, on the basis of the effective antigen, the other, homoeopathy, on the basis of the effective antigen, the other, homoeopathy, on the basis on the characteristic symptomatology of the bloody reaction. The former lends itself readily to routinism. The latter antagonizes routinism.
Regarded in this light, then, isopathy and homoeopathy are diametrically opposed in principle, although it is true that in a given case the use of both principles may result in the selection of the same remedy. Inasmuch as this also may occur when the physiologic and the homoeopathic principle are employed in a given case, this coincidental fact can be of no value as a proof of close relationship.