Volume 1

The elements of materia medica : comprehending the natural history, preparation, properties, composition, effects and uses of medicines / by Jonathan Pereira, F.R.S. & L.S.

  • Pereira, Jonathan, 1804-1853.
Date:
1839-1840
Catalogue details

Licence: Public Domain Mark

Credit: The elements of materia medica : comprehending the natural history, preparation, properties, composition, effects and uses of medicines / by Jonathan Pereira, F.R.S. & L.S. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    sessing great volatility and power of expansion, by which it is enabled to diffuse itself through the blood more rapidly than that fluid circulates, to permeate the animal tissues very quickly, and in a manner independent of its distribution by means of the blood, and thus to produce the pecu- liar material changes in the central organ of the nervous system more 4 quickly in proportion as it is applied nearer to it.”—{Op. cit. p. 247.) b. The effects being disproportionate to the facility for absorption.— Orfila (Toxicologie Generate) says, that alcohol acts with much less energy when injected into the cellular texfure, than when taken into the stomach ; and as the power of absorption is greater in the former than in I the latter part, he concludes that the remote action of alcohol must be produced by the agency of the nerves. Opium, on the contrary, is sup- posed to operate by absorption, because it is more active when injected | into the cellular texture of the thigh than when taken into the stomach. c. Dilution diminishing the remote effects.—The effect of dilution on the action of medicinal and poisonous agents oftentimes assists us in determining the mode by which the remote effects take place.' Thus if we apply a strong mineral acid to the stomach, great disorder of the general system is produced; but if we dilute the acid previous to its j exhibition, little disturbance in the system is observed. Now as dilution f facilitates absorption, it is improbable that the constitutional disorder caused by swallowing strong mineral acids depends on their absorption, i On the other hand, Dr. Christison {op. cit.) has shown that oxalic acid, \ considerably diluted, quickly enters the blood, and causes speedy death : I hence it is presumed to kill in consequence of absorption. d. Effect of Mechanical Injury.—Mechanical injuries sometimes give ji rise to effects on remote parts similar to those caused by the action of I certain medicines or poisons. Laceration of the stomach produces similar I constitutional disorder to that occasioned by the strong acids. Agency of the Nervous System.—Between the individual parts of ji the organism there exist certain relations or connexions, which Adelon (.Physiologie de VHomme, t. 4me, p. 200,) has arranged in three classes,— j the mechanical, the functional, and the sympathetic. It frequently happens n that one organ in the performance of its functions exercises a mechanical influence over another. Thus the motions of the respiratory muscles | have an important influence over the circulation of blood within the chest. By the contraction of the muscles of the fore-arm, pressure is made on the deep-seated veins, and the passage of blood through them thereby obstructed. These, then, are evident and clear cases of a mecha- nical relation between certain organs. We have also numerous instances of what have been called functional relations; but one example will suffice : the liver cannot secrete bile if the supply of arterial blood, or of! nervous energy, be cut off: hence it is evident that the function of the liver depends for its performance on the proper execution of the functions of the arterial and nervous systems. But there is a class of relations which cannot be referred to either of the preceding heads, and which have been called the true sympathies, or the sympathetic relations. Thus if we titilate the mucous membrane of the nose, sneezing is produced; if the soft palate, vomiting. j The phenomena hitherto called sympathetic have been denominated by Dr. Marshall Hall {Memoirs on the Nervous System, 1837,) excito- t motory. They must not be confounded with those of sensation and 1 1