176 THE POPULAR SCIENCE MONTHLY 



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 sponges swallowed and withdrawn, are familiar.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 chymiflcation is eff"ected 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 pres- 

 ence 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 hon- 

 ored by the Academie 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^ 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 sup- 

 posed 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 



^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. 



