In making a direct attack upon the pretentions of Homoeopathy, Doctor Holmes declares at the outset that he shall treat it not by ridicule, but by argument; with great freedom, but with good temper and in peaceable language. _Similia similibus curantur._ Like cures like, is one of the fundamental principles of Homoeopathy, and "improbable though it may seem to some," says Doctor Holmes with his usual impartial fairness, "there is no essential absurdity involved in the proposition that diseases yield to remedies capable of producing like symptoms. There are, on the other hand, some analogies which lend a degree of plausibility to the statement. There are well-ascertained facts, known from the earliest periods of medicine, showing that under certain circumstances, the very medicine which from its known effects, one would expect to aggravate the disease, may contribute to its relief. I may be permitted to allude, in the most general way, to the case in which the spontaneous efforts of an over-tasked stomach are quieted by the agency of a drug which that organ refuses to entertain upon any terms. But that _every_ cure ever performed by medicine should have been founded upon this principle, although without the knowledge of a physician, that the Homoeopathy axiom is, as Hahnemann asserts, "the _sole_ law of nature in therapeutics," a law of which nothing more than a transient glimpse ever presented itself to the innumerable host of medical observers, is a dogma of such sweeping extent and pregnant novelty, that it demands a corresponding breath and depth of unquestionable facts to cover its vast pretensions." Among the many facts of which great use has been made by the Homoeopathists, is that found in the precept given for the treatment of parts which have been frozen, by friction with snow, etc. "But," says Doctor Holmes, "we deceive ourselves by names, if we suppose the frozen part to be treated by cold, and not by heat. The snow may even be actually _warmer_ than the part to which it is applied. But even if it were at the same temperature when applied, it never did and never could do the least good to a frozen part, except as a mode of regulating the application of what? of _heat_. But the heat must be applied _gradually_, just as food must be given a little at a time to those perishing with hunger. If the patient were brought into a warm room, heat would be applied _very rapidly_, were not something interposed to prevent this, and allow its gradual admission. Snow or iced water is exactly what is wanted; it is not cold to the part; it is very possibly warm, on the contrary, for these terms are relative, and if it does not melt and let the heat in, or is not taken away, the part will remain frozen up until doomsday. Now the treatment of a frozen limb by heat, in large or small quantities, is not Homoeopathy."