Page:Popular Science Monthly Volume 74.djvu/180

and the ways in which gastric fluid was removed by squeezing out sponges swallowed and withdrawn, are familiar. The impression which these researches left is well emphasized by Beumont. He wrote (1833):

Suffice it to say that the theories of Concoction, Putrefaction, Trituration, Fermentation and Maceration, have been prostrated in the dust before the lights of science, and the deductions of experiment. It was reserved for Spallanzani to overthrow all these unfounded hypotheses, and to erect upon their ruins, a theory which will stand the test of scientific examination and experiment. He established a theory of chemical solution, and taught that chymification was owing to the solvent action of a fluid, secreted by the stomach, and operating as a true menstruum of alimentary substances. To this fluid he gave the name of gastric juice. . . . By far the most respectable and intelligent physiologists have now settled down in the belief that chymification is effected in the stomach, by a specific solvent, secreted by that organ, called, after spallanzani, the Gastric Juice. From the difficulty, however, of obtaining and submitting this fluid to the test of experiment, and the diversity of results in the examination of such as has been obtained, no very satisfactory conclusions have been arrived at. The presence of an active solvent is rather an admission—a conclusion from the effect to the cause.

Spallanzani failed to understand the acid character of solvent gastric juice. Even as late as 1825 Leuret and Lassaigne, in a memoir honored by the Académie des Sciences, declined to accept Front's evidence of the existence of hydrochloric acid in the gastric secretion. This deserves notice with reference to the experiments of Dr. Young which will be described later.

Young's essay opens with a review of the Nutrientia, the views of Dr. Cullen being subjected to criticism. This famous Edinburgh teacher^[1] referred "the principal of nutrientia to vegetables; and that they derive this property from their acid, sugar and oil." Taking these up in order, Young rejects acid as a true nutrient, with these words:

The doctor (Cullen) appears to have founded his opinion on the idea, that all vegetable substances, when taken into the stomach, undergo a fermentation, whereby an acid is evolved; and "as this entirely disappears with the progress of the aliment, without being again evident in the mass of blood," so he supposed it undoubtedly entered into the composition of the animal fluid. That an acetous fermentation takes place in the human stomach in a healthy state, we entirely reject, as will appear in what follows; and if this opinion be well founded, we obviate the principal argument favouring the idea, of an acid being nutritious. Acescent vegetables we can not doubt as affording nourishment, but this is not to be referred to their acid, but to their sugar and oil.

Young overthrows Cullen's assumption that "sugar is not alimentary in its pure saline state, but only when combined with an oleaginous

---

1. I have assumed that the writer must refer to William Cullen (1712-90), of Edinburgh, under whose influence the abler young men from the English colonies in America came.