This section is from the book "A Compend Of The Principles Of Homoeopathy", by William Boericke. Also available from Amazon: A Compend of the Principles of Homoeopathy as Taught by Hahnemann.
Without the necessity of accepting the Psoric doctrine as a whole, the homoeopathic school has found in it an excellent working hypothesis, and certain facts are undeniable and go far to establish the essential truth of the doctrine. These are the following:
1. In many patients, the even and regular clinical course of diseases is from some course or other within themselves interfered with.
2. Remedies apparently indicated and chosen according to the law of similars, fail to accomplish what, as a rule, they ought.
3. This is especially true of most chronic diseases.
4. It is a further fact that frequently the suppression or disappearance of a skin disease is followed by serious mischief in more vital organs, as respiratory affections (asthma), after eczema capitis, etc., showing a reciprocal relation between the skin and internal organs.
It is the presence of this unseen but nevertheless very active and perturbing factor that accounts for these conditions. Now, this fact of recognition is the mark of genius. The theory of its precise nature is of comparatively little importance and may or may not be true. That it is nothing but suppressed itch in the narrow sense is not true. That, however, suppressed skin affections in a wider acceptation than what we now-a-days understand by itch are an indubitable factor in the production of many forms of obstinate and occult chronic suffering far removed from local skin manifestation, is an established truth. The Hahnemannian conception of Psora is a very real thing, the Psora theory an intensely practical thing and that is its passport to the general practitioner whose aim is to cure permanently rather than palliate and relieve for the time being. Perhaps it would have been better not to try and define the inner essence of this dyscrasia. The celebrated Botanist Schleiden, used to open his lectures on Botany by frankly confessing that he did not know what a plant was. So we may not know what Psora is, except that it consists of the sum of all the biological obstacles which resist, deface, complicate and alter the natural course of diseases and interfere with the action of the apparently well selected homoeopathic remedy. In this wider sense, as indicating cachexia or dyscrasia, the Psora theory is founded in nature and truth. Though Hahnemann's theory is not proven, it is a most admirable working theory, a stepping stone by means of which we attain remarkable results in the treatment of disease.
Anti-psoric remedies are such as show in their pathogenesis a tendency to act from within outwards, from above downwards, who thus abound in skin symptoms and are deep and long-acting remedies; hence, they are of special value in the treatment of chronic disease and for the eradication of inherited and constitutional disease tendencies. They show their greatest medicinal power in highly attenuated form and do not bear frequent repetition. Many of them are wholly inert in their crude state and require the pharmaceutical processes of homoeopathy to develop their latent medicinal force.
The principal anti-psoric remedies are Sulphur, Cal-carea, Lycopodium, Sepia, Silica, Natrum mur., Graphites, Arsenic, Alumina, etc. *