The nature of homoeopathy.

It has been customary to define hom0eopathy in terms of the so-called Similia principle, that is to say in practical terms that one should treat a disease with a remedy which can cause in a healthy person a similar disturbance. For instance, for diarrhoea one should, according to this principle, give castor oil or a similar aperient rather than an opium derivative or mixture given on the principle of treatment with opposites. One can trace both ideas back to the Hippocratic writings and indeed the treatment with similars has a much longer history, being the essential basis of much magical medicine in what we like to regard as primitive times. Sir James Fraser in the Golden Bough uses the expression homoeopathic magic to cover a whole realm of these ancient practices. But I shall have to show that it is not as simple as it at first sounds or as it is usually presented. It further belongs to the commonly accepted ideas about homeeopathy that in this therapeutic system very small doses of medicine are given, the so-called potencies, and many people, both lay and professional, know only that a hom0eopathic dose is one so small that it cannot harm you anyway, let alone do you any good. In addition it is often emphasized that the homoeopathic materia medica is based on naturally occurring substances from the animal, vegetable or mineral kingdoms rather than the artificially constructed and manufactured products of the pharmaceutical industry. It is probably because of this distinction and the emotive terms in which it is easy to state the difference, that homceopathy is often grouped with natural therapies. This last distinction between hom0eopathy and the traditional orthodox medicine, often referred to as allopathy, was not relevant when Samuel Hahnemann introduced his revolutionary method at the beginning of the nineteenth century. The vast majority of the remedies in the hom~eopathic materia medica were and are the same as those in common use in the conventional medicine of those days, mostly traditional medical plants, many dating back to classical antiquity and beyond. Minerals and metals were also included, some also from traditional sources. Gradually additions have been made from, for instance, American Indian folk remedies and from the poisons of serpents, spiders and so on. It is therefore an issue which only assumes importance within the climate o f present-day anxieties over the pollution of our inner and outer environment by the synthetic products of modern industry. It would be difficult, however, to find