for a disease when we know that it produces in the (relatively) healthy human organism irresistibly, i.e. without the co-operation of another factor, reactive phenomena which are identical with those of the disease produced by relative causes ?

It is absolutely necessary to answer this question if we would supply a basis consonant with natural laws for the "practical deductions" demanded by the thesis proposed for the prize essay.

This is not the place to give the genesis of Hahnemann's doctrine, which I take for granted is already well known in spite of the many distorted representations that are current respecting it. One thing only I cannot pass over in silence because it contains the experimental presupposition of what follows, namely, that Hahnemann, after he had instituted a pathogenetic proving of a series of medicinal substances on relatively healthy human organisms, and had found that the organic phenomena of reaction obtained therefrom stood in the most perfect relation of similarity to those diseases for which they had been empirically recognised as their specific remedies, deduced the existence of a law of nature, which was the rule of the curative process. After clinical experience, which taught him that the rarefaction of the substance of the drug was a condition for its curative effect, had proved its existence he formulated the law of similarity. Out of this has arisen a not altogether unfounded reproach made by both friends and foes, which owes its origin to a mistaken conception on his side. What sort of similarity Hahnemann had in his mind may be easily ascertained if we remember that he was fundamentally trained in a mathematico-philosophical school. He was a disciple of Lambert, who gave to logic a mathematical basis, and was one of the first who acknowledged the wonderful genius of Imanuel Kant. Therefore it could be only the geometrical idea of similarity which he had in his mind. This applies, among other things, to two triangles, which though having unequal lengths of their sides have identical angles, whereas two triangles that have identical angles and sides are termed congruent VOL. XLI, NO. CLXVI.-OCTOBER, 1883.

because they cover one another perfectly. But in his Organon, when speaking of similarity, Hahnemann expressly insists on this congruence, for he only allows to be the specific remedy a medicine whose pathogenetic sphere of action completely includes those phenomena which constitute the object of cure. He would have done better to have borrowed the designation of the law of cure discovered by himself from the idea of congruence and to have called it the law of identity, for, in truth, the strictly contradictory antithesis that obtains between poison and medicine or remedy is only met within the sphere of identity. An excuse for this misconception lies in the circumstance that, when we compare the many accidents of two things with one another it is, without doubt, the similarity, the concordance of one or several of the accidents common to the two things, which first strikes us, and it is only by a prolonged and far-searching comparison that we recognise their identity, i.e. the complete concordance of the accidents common to both things, when that exists. In the sense usually underlying the common acceptation of the designation "similarity" the law of similarity can only be regarded and serve as a heuristic rule for the search for specific remedies; but it can never lead to the discovery and formulating of a law of nature, for there cannot be two things that have not at least one accident in common, i.e. which in the sense of ordinary language do not stand in some, however remote, similarity to one another. Therefore, when I speak hereafter of the law of similarity I beg the reader to understand by that term the law of identity.

Without this rectification or transformation, which I have proposed in Hahnemann's mode of expressing himself, the specific curative process is not susceptible of the scientific explanation which is possible by the law of polarity included in the law of identity. It was not until post-Hahnemannic times that it was ascertained that it is the law of polarity that regulates all the movements of organic life. The reactive power of the vegetable and animal organism in all stages of its development is dependent upon it. Had Hahnemann found this concep

tion distinctly formulated, for which some of his illustrious contemporaries had, indeed, contributed the first hints, and had he been able to interweave them with all his own scientific thinking, his attempts at an explanation of the specific artificial curative process would have been more successful. But his critical penetration enabled him to divine the conclusion to which this knowledge must lead; and in the index to the Organon he introduces his attempt. at an explanation with the modest words-" what probably takes place in the homeopathic cure;" still it may serve as a kind of sketch which may be filled up by means of the colours which the information we have acquired in recent times have supplied us with.

Hahnemann supposes that the very small dose of the remedy produces in the diseased organ a second artificial disease, which by reason of its greater strength supplants the natural disease, and thereupon, on account of the smallness of the medicinal dose, is easily overcome by the vital power.

The insufficiency of this explanation, which commences with a petitio principii and concludes with an obvious contradictio in adjecto, is quite evident, and requires no proof. But it would be at once rectified if we substitute for Hahnemann's supposititious "artificial disease" the term "artificial morbific cause." It is easy to understand wherein the "greater strength" of this consists, whereby the natural morbific cause is supplanted, when we remember the difference pointed out above, which divides the morbific cause into relative and absolute. We know that the latter has a much greater affinity to the morbid process, a stronger causal relation to its action than the former, the relative morbific cause, which we have seen to be unable to produce a specific morbid process without the presence of a second factor, the constitutional morbid predisposition or specific individual capability of being morbidly affected. If we keep this affinity in view we can understand that the single dose of the specific remedy selected according to the law of similarity, inasmuch as after its ingestion it encounters pre-existing pathogenetic

actions in the disease specifically identical with those of the medicine, obtains the significance of the actual cause of the disease to be cured, and it is in this character that it, by virtue of its stronger affinity to the pathological process present, dissevers from its connection the pre-existing relative morbific cause.

If Hahnemann, when he applied to the law of cure he discovered the term law of similarity, departed from the commonly accepted meaning of the word as we have seen; when he attempted an explanation of it, he acted quite in conformity with the usual mode of speech, for he attributed to the minimal medicinal dose a disease-producing action, which it neither can nor should have.

When we have witnessed for a long time and in many cases the true specific artificial treatment of disease, have got over our first surprise, the mother of philosophical reflection, have become familiar with the gratifying spectacle of unexpectedly rapid cure, have got rid of prejudices which tend to obscure our judgment, and have thus been elevated to the position of passive recipients of pure knowledge, have, so to speak, lost ourselves in the sphere of observation, in such a manner as that the observing subject has become capable of acting as a true mirror of the object observed, we no longer require to ascribe to the artificial cause that sets in action the curative process, i.e. to the minimal dose, an action in the vulgar acceptation of the term. This attaches unconsciously to the word "action" the idea of positive action, which presupposes the factor-quantity. But as we, in conformity with Hahnemann's procedure, employ with complete success, for the cure of morbid processes of the most serious character, which threatened to run a long course, or even a speedy fatal termination, the smallest doses of medicine, respecting the quantity of which we cannot form any adequate conception, so neither can we form any conception of the positive action which we unconsciously attribute to the curative medicinal dose. As the positive action of pre-existent or still persisting causes we have the disease before us, the disease is; in conformity with the wish of the patient, or of those around him, it is not to be;

here language itself if we will allow it to speak, instead of dictating to it what it should say, lays down the postulate of the negative medicinal curative action. This is what Hahnemann has realised by the rarefaction of the medicinal substance, without having been able to find an appropriate designation for it, and by virtue of which the factor of quantity capable of causing a positive morbific action is set aside, whilst the factor of specific quality agreeably to the law of the infinite divisibility of matter is maintained, and proves the possibility of negative medicinal, which is potentially curative, action.

After the ingestion of the single dose of a remedy selected in accordance with the law of similarity, only three things are possible:

Either it increases the intensity of the morbid processes to the square, if by reason of its quantity it causes the positive action;

Or it behaves itself indifferently, if its quantity hovers on the boundary betwixt the two poles;

Or, lastly, it acts negatively, if that boundary be sufficiently overstepped in the direction of the negative pole. Quartum non datur.

The cure by art is the negative, the undoing of the disease so to speak.

After this necessary digression I return to the special object of this essay.

It may be urged as a reproach against the accidental observation, which served as the experimental preliminary to the first employment of Cyanuret of Mercury for the cure of diphtheria, that it was not observed in a sufficient number of cases. But on the other hand there is this to be said, that the two substances that together make the salt in question, have already been singly subjected to a tolerably exhaustive pathogenetic proving. The character of the chemical combination does, it is true, necessitate the production of a new body with new physical properties which did not exist in the separate constituents of the salt; it would seem, however, that this rule does not extend to the organic reaction caused by them, on which