Copy 1, Volume 1

The study of medicine. Improved from the author's manuscripts, and by reference to the latest advances in physiology, pathology, and practice / [John Mason Good].

  • Good, John Mason, 1764-1827
Date:
1834
Catalogue details

Licence: Public Domain Mark

Credit: The study of medicine. Improved from the author's manuscripts, and by reference to the latest advances in physiology, pathology, and practice / [John Mason Good]. Source: Wellcome Collection.

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    bulbus glandulosus, situated at the lower end of the gullet; the structure of the gizzard being evidently not adapted to its secre- tion. In birds, therefore, digestion is produced by a powerful solvent, just as it is in the human subject. ] The gastric juice, this wonderful menstruum, the most active we are acquainted with in nature, is secreted, as I have already observed, by the capillary arteries that infinitesimally intersect the cellular texture of the stomach, and decussate each other in their ramifications. ‘The quantity secreted during digestion is consider- able: Leuret and Lassaigne found, that when the gullet of a horse was tied, so as to prevent the secretions of the mouth and gullet from entering the stomach, a full meal of oats became completely saturated with gastric juice in four or five hours. Mr. Cruickshank supposes the quantity of the fluid, thus secreted, to be about a pound in every twenty-four hours. Yet the quantity seems to vary considerably, according to the demand of the system, or the state of the stomach itself. In carnivorous birds, whose stomachs are called membranous from having little muscularity, and, conse- quently, whose food is turned into chyme principally by the action of the gastric juice, without any collateral assistance or previous mastication, this fluid is secreted in a much larger abundance; as it is also in those who labour under that morbid state of the stomach which is called canine appetite, and will be distinguished in the present classification by the name of limosis avens; as likewise when, on recovery from a fever, or after long abstinence, the system is reduced to a state of great exhaustion, and a keen sense of hunger induces a desire to devour food voraciously and almost perpetually. [If the contents of the stomach be examined after a long fast, and without any stimulus being applied to its villous membrane, the fluid found in it is a clear, ropy, rather opaque liquid, nearly or quite destitute of acidity. But if any stimulus, even of the simplest kind, be applied to the inside of the stomach, then the fluid secreted is uniformly acid. Hence, during digestion, it is found to be dis- tinctly acid; indeed, free muriatic acid was detected during this process by Dr. Prout in the stomach of the rabbit, hare, horse, calf, and dog (Phil. Trans. 1824); and also in the matter ejected from the stomach of persons labouring under indigestion. ‘Tiedemann and Gmelin obtained the purest gastric juice by making animals swallow quartz pebbles after a long fast, and killing them an hour afterwards. It was generally greyish-white, ropy, and decidedly acid. When taken from the dog and the horse, it contained some mucus, osmazome, and salivary matter, alkaline sulphates, and hydrochlorates, the alkali being chiefly soda, besides phosphate and muriate of lime, with other salts in minute proportion; and the acidity was owing to the hydrochloric and acetic acids in the dog, and to these conjoined with the butyric acid in the horse. As the lactic acid of Leuret and Lassaigne is now acknowledged by Berzelius to be a variety of the acetic, all parties may be regarded as agreeing about the presence of that acid in the gastric juice. The researches of Prout, Children, and Graves, confirmed as they have been so amply by Tiedemann and Gmelin, also fully establish the presence of free muriatic acid. When the secretion of the gas- tric juice is elicited by its natural stimulus, food of various kinds, Quantity of the gas- tric juice, Qualities of the gas- tric juice.