PHARMACOLOGIA. ON THE OPERATIONS OF MEDICINAL BODIES, AND ON THE CLASSIFICATIONS FOUNDED ON THEM. (continued 3)

In the use of water upon such occasions, it may moreover be observed, that its temperature ought to be attended to; as a general rule it may be 141laid down, that in the cold stage it should be hot, in the hot, cold, and in the sweating, tepid.

With regard to the value of diluents, as capable of promoting the operation of other remedies, many observations of great practical importance might be adduced; but this subject will be more properly elucidated when we come to consider the influence of solubility in modifying the activity of medicinal substances, and which constitutes a very curious and interesting object of chemico-medical enquiry.

While speaking of Diluents it may be cursorily noticed, that water appears, under certain circumstances of the body, to suffer decomposition, and to have its elements appropriated to new combinations. Count Rumford has endeavoured to prove, that the surprisingly small quantity of solid food which is sufficient for nourishment, when converted into rich and palatable soup, is owing to the culinary process having prepared the water for chemical decomposition,^[237] and that this is ultimately effected during the act of Digestion.^[238] It cannot be denied that the exorbitant potation of water has a tendency to produce fat, but this may depend upon the vascular distention which is thus occasioned. Gin drinkers, before they become materially injured by the habit, grow extremely corpulent, as may often be witnessed in unfortunate cyprians of the lower orders. Can the hydrogen of the spirit contribute to this effect?

EMOLLIENTS:

Substances whose application diminishes the force of cohesion in the particles of the solid matter of the human body, and thereby renders them more lax and flexible.

According to this definition, which we derive from Dr. Cullen, the primary operation of emollients would appear to be purely mechanical, for they are insinuated into the matter of the solid fibre, and either diminish its density, or lessen the friction between its particles; this explanation will undoubtedly apply to those emollients which consist of unctuous bodies, and which are introduced into the animal fibre by friction; but it is evident that the beneficial effects of Cataplasms and Fomentations cannot be so explained; for in these instances, none of the materials can be absorbed through the entire cuticle; and yet the relaxation and consequent ease which such warm applications produce on inflamed surfaces is very considerable, but it must be wholly attributed to the relaxing effects of warmth and moisture upon the extreme vessels of the surface, propagated by contiguous sympathy to the deeper seated organs.

The operation of those substances which afford relief to excoriated surfaces by their bland qualities, as mucilaginous lotions in erysipelatous affections, is too obvious to require explanation.

Having thus investigated the manner in which medicinal substances produce their effects upon the living system, we shall be better prepared to appreciate the advantages which are to be derived from their combination with each other, and to escape the too common error of uniting in one formula, remedies which are rendered adverse by the incompatibility of their physiological actions.

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ON THE

THEORY AND ART

OF

PRESCRIBING.

“To know

“That which before us lies in daily life,

“Is the prime wisdom.”

Milton.

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