GASTRIC JUICE, AND STOMACH DIGESTION. 143 



cheese is entirely converted into albuminose, and dissolved under 

 that form. A very considerable portion of raw white of egg, how- 

 ever, dissolves in the gastric juice directly as albumen, and retains 

 its property of coagulating by heat. Soft-boiled white of egg and 

 raw meat are principally converted into albuminose ; but at the 

 same time, a small portion of albumen is also taken up unchanged. 



The above process is a true liquefaction of the albuminoid sub- 

 stances, and not a simple disintegration. If fresh meat be cut into 

 small pieces, and artificially digested in gastric juice in test-tubes, 

 at 100 F., and the process assisted by occasional gentle agitation, 

 the fluid continues to take up more and more of the digestible 

 material for from eight to ten hours. At the end of that time if it 

 be separated and filtered, the filtered fluid has a distinct, brownish 

 color, and is saturated with dissolved animal matter. Its specific 

 gravity is found to have increased from 1010 to 1020 ; and on the 

 addition of alcohol it becomes turbid, with a very abundant whitish 

 precipitate (albuminose). There is also a peculiar odor developed 

 during this process, which resembles that produced in the malting 

 of barley. 



Albuminose, in solution in gastric juice, has several peculiar 

 properties. One of the most remarkable of these is that it inter- 

 feres with the operation of Trommer's test for grape sugar (see 

 page 84). We first observed and described this peculiarity in 

 1854, ' but could not determine, at that time, upon what particular 

 ingredient of the gastric juice it depended. A short time subse- 

 quently it was also noticed by M. Longet, in Paris, who published 

 his observations in the Gazette Hebdomadaire for February 9th, 

 1S55. J He attributed the reaction not to the gastric juice itself, 

 but to the albuminose held in solution by it. "We have since found 

 this explanation to be correct. Gastric juice obtained from the 

 empty stomach of the fasting animal, by irritation with a metallic 

 catheter, which is clear and perfectly colorless, does not interfere 

 in any way with Trommer's test ; but if it be macerated fur some 

 hours in a test-tube with finely chopped meat, at a temperature of 

 100, it will then be found to have acquired the property in a 

 marked degree. The reaction therefore depends undoubtedly upon 

 the presence of albuminose in solution. As the gastric juice, drawn 

 from the dog's stomach half an hour or more after the introduction 



1 American Journ. Med. Sci., Oct. 1854, p. 319. 



2 Nouvelles recherches relatives a 1'action du sue gastrique sur les substances 

 albuminoides. Gaz. Hebd. 9 F'vrier, 1855, p. 103. 



