GASTRIC JUICE, AND STOMACH DIGESTION". 141 



common glass-stoppered bottle without developing any putrescent 

 odor. A light deposit generally collects at the bottom, and a con- 

 fervoid vegetable growth or "mould" often shows itself in the fluid 

 after it has been kept for one or two weeks. This growth has the 

 form of white, globular masses, each of which is composed of deli- 

 cate radiating branched filaments (Fig. 30) ; each filament consisting 

 of a row of elongated cells, like other vegetable growths of a similar 

 nature. These growths, however, are not accompanied by any 

 putrefactive changes, and the gastric juice retains its acid reaction 

 and its digestive properties for many months. 



By experimenting artificially with gastric juice on various ali- 

 mentary substances, such as meat, boiled white of egg, &c., it is 

 found, as Dr, Beaumont formerly observed, to exert a solvent action 

 on these substances outside the body, as well as in the cavity of the 

 stomach. This action is most energetic at the temperature of 100 

 F. It gradually diminishes in intensity below that point, and ceases 

 altogether near 32. If the temperature be elevated above 100 

 the action also becomes enfeebled, and is entirely suspended about 

 160, or the temperature of coagulating albumen. Contrary to 

 what was supposed, however, by Dr. Beaumont, and his predeces- 

 sors, the gastric juice is not a universal solvent for all alimentary 

 substances, but, on the contrary, affects only a single class of the 

 proximate principles, viz., the albuminoid or organic substances. 

 Neither starch nor oil, when digested in it at the temperature of 

 the body, suffers the slightest chemical alteration. Fatty matters 

 are simply melted by the heat, and starchy substances are only 

 hydrated and gelatinized to a certain extent by the combined influ- 

 ence of the warmth and moisture. Solid and semi-solid albuminoid 

 matters, however, are at once attacked and liquefied by the diges- 

 tive fluid. Pieces of coagulated white of egg suspended in it, in a 

 test-tube, are gradually softened on their exterior, and their edges 

 become pale and rounded. They grow thin and transparent; 

 and their substance finally melts away, leaving a light scanty de- 

 posit, which collects at the bottom of the test-tube. While the 

 disintegrating process is going on, it may almost always be noticed 

 that minute, opaque spots show themselves in the substance of the 

 liquefying albumen, indicating that certain parts of it are less easily 

 attacked than the rest; and the deposit which remains at the bot- 

 tom is probably also composed of some ingredient, not soluble in 

 the gastric juice. If pieces of fresh meat be treated in the same 

 manner, the areolar tissue entering into its composition is first 



