Pharmacologia; comprehending the art of prescribing upon fixed and scientific principles; together with the history of medicinal substances / By J.A. Paris, with notes and additions.

  • Paris, John Ayrton, 1785-1856.
Date:
1828
Catalogue details

Licence: Public Domain Mark

Credit: Pharmacologia; comprehending the art of prescribing upon fixed and scientific principles; together with the history of medicinal substances / By J.A. Paris, with notes and additions. Source: Wellcome Collection.

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    their density, but that, of substances of equal density, those which possess^ ed the refractive power in a higher degree were inflammable.* Analo¬ gy induced him to conclude that, on tliis account, water must contain an inflammable principle, and Experiment enabled Cavendish and Lavoisier to demonstrate the surprising truth of IVewton’s induction in their immor¬ tal discovery of the chemical composition of that fluid. The history of Astronomy furnishes another illustration equally beauti¬ ful and instructive.—The Astronomer observed certain oscillations in the motions of Saturn and Jupiter; by Analogy he conjectured that this phe¬ nomenon was produced by the influence of a planet still more remote : a supposition which was happily confirmed by a telescopic experiment^ in the discovery of Uranus, by Herschel. But it is clear that such principles of research, and combination of methods, can rarely be applied in the investigation of remedies, for every problem which involves the phenomena oflife is unavoidably embarrassed by circumstances, so complicated in their nature, and fluctuating in their operation, as to set at defiance every attempt to appreciate their influ¬ ence ; thus an observation or experiment upon the effects of a medicine is liable to a thousand fallacies, unless it be carefully repeated under the various circumstances of health and disease, in different climates, and on^ different constitutions. We all know how very differently opium or mer- ^ cury will act upon different individuals, or even upon the same individu¬ als, at different times, or under different circumstances; the effect of a sti¬ mulant upon the living body is not in the ratio of the intensity of its impulse, but in proportion to the degree of excitement, or vital susceptibility of the individual to whomit is applied. This is illustrated in a clear and familiar manner, by the very different sensations of heat which the same temperature will produce under different circumstances. In the road over the Andes, at about half way between the foot and the summit, there is a cottage in which the ascending and descending travellers meet; the former, who have just quitted the sultry vallies at the base, are so relax¬ ed, that the sudden diminution of temperature produces in them the feeling of intense cold, whilst the latter, who have left the frozen summits of the mountain, are overcome by the distressing sensation of extreme heat. But we need not climb the Andes for an illustration ; if we plunge one hand into a basin of hot, and the other into one of cold water, and then mix the contents of each vessel, and replace both hands in the mixture, we shall experience the sensation of heat and cold, from one and the same medium ; the hand, that had been previously in the hot, will feel cold, whilst that which had been immersed in the cold water, will experi¬ ence a sensation of heat. Upon the same principle, ardent spirits will pro¬ duce very opposite effects upon different constitutions and temperaments, and we are thus enabled to reconcile the conflicting testimonies respecting the powers of opium in the cure of fever: aliment?^, also, which under ordinary circumstances would occasion but little eflect, may in certain conditions of the system, act as powerful stimulants ; a fact which is well exemplified by the history of persons who have been enclosed in coal mines for several days without food, from the accidental falling in of the * The refractive power of an inflammable body bears also a proportion to its per¬ fection, whence it may be sometimes used as a test of its purity; thus Dr. Wollaston found that genuine Oil of Cloves had a refractive power of 1.535, while that of an inferior quality did not exceed 1.490.