(From The Science of Therapeutics).
THE symptoms which drugs produce upon the healthy organism vary according to the dose. They may be:.
1. CHEMICAL-depending on the chemical affinity which exists between the drug and the tissues of the body, and independent of vitality; or.
2. MECHANICAL (or revolutionary)-consisting chiefly in violent efforts on the part of the organism to eject from its cavities the offending substance; or.
3. DYNAMIC-contingent upon vitality and resulting from the relations of the peculiar properties of the drug of the susceptibilities of the living, healthy organism. These dynamic effects may be:.
(a) Generic-such as are common to all the members of a certain class of drugs and which serve to distinguish this class from others, but do not furnish means of distinguishing between different individuals of the same class. For example, ARsenic in certain doses produces vomiting and diarrhoea, with cold sweat and cramps of the extremities.
These are dynamic effects of ARsenic, but they are generic, since other members of the class to which Arsenic belongs, viz. Cuprum, Veratrum, Tartar emetic, etc., in certain doses, produce identical symptoms; and were these remedies proved in such doses alone, it would be impossible to distinguish the pathogenesis of one of them from that of any of the others.
(b) Specific-such as results from the dynamic action of the drug and are peculiar to it. They serve to distinguish a give drug from all others. For example, Arsenic, taken in different doses from those which produce the generic dynamic effects, produced vomiting and diarrhoea or tendencies thereto; but these phenomena are accompanied and characterized by conditions quite different from those which accompany the similar symptoms of Cuprum, Veratrum, etc., and are thus distinguishable from the effects of these drugs.
The Specific dynamic symptoms may be again subdivided into Central and PEripheral.
The Central symptoms appear speedily after the drug is taken, are generally the result of comparatively large doses and, in the case of many drugs, are confined to the alimentary canal and to the organs immediately connected with it.
The Peripheral symptoms appear more tardily, are generally the result of comparatively small doses, taken repeatedly or allowed to act without interruption for a long period, and appear in the bones, skin, glands, etc., and in the co-ordinated phenomena of life. They are often the manifestations of a dyscrasia or cachexy. Doses which produce central symptoms do not generally produce the peripheral (or at least not till after a long period has elapsed) and vice versa.
For example, Mercury, in certain doses, produces well-marked and characteristic action upon the alimentary canal and its appendages. In smaller doses it produces, instead of these effects, a series of symptoms in skin, bones, glands, etc., the Mercurial cachexy. The former are what we mean by central specific dynamic symptoms. The latter are the peripheral symptoms. Arsenic, again,furnishes, according to dose, examples of all the above varieties of symptoms. In certain doses it develops chemical and revolutionary effects.
In smaller doses, as we have seen, generic dynamic; in still smaller doses, specific dynamic symptoms of the central variety. In yet smaller doses, it produces peripheral specific symptoms, which are those of the so-called “gradual poisoning”; as for instance in poisoning by exhalations of Arsenic from green wall-paper, in which the phenomena of vomiting and diarrhoea, or the central specific symptoms do not appear, but instead of these we have evidence of the distinct cachexy, in the skin and glandular symptoms, marasmus, etc.
Such are the varieties of symptoms produced by corresponding varieties in the dose. It is hardly necessary to say that they are not always to be distinguished with precision; but the facility with which we are able to recognize them is in proportion to the completeness of our proving.
It unquestionably behoves the homoeopathic physician to have an exhaustive knowledge of the whole sphere of action of his drugs; but, as a prescriber, he must be familiar with the varieties and sub-varieties of dynamic effects which we have specified. This knowledge is to be obtained in the first place only by drug- proving. The proving of drugs must then be so conducted as to produce in the greatest possible completeness and clearness, each of these varieties and sub-varieties. This, as has been shown, is to be accomplished by a skillful selection and succession of doses. It is not so simple and easy a matter, as it might at first view appear to be: for.