PEPTONE. 



IT was in the early years of the present century that the 

 most important discovery was made that the secretion 

 of the glands of the stomach is an acid one ; and Carl 

 Schmidt was the first to show with analytical certainty that 

 it is hydrochloric acid which is par excellence the acid of the 

 gastric juice. The presence of other acids like lactic acid 

 is more or less accidental. The absence of putrefaction in 

 the normal gastric contents was noted by Spallanzani, 

 and is caused by this acid. There can be no doubt that 

 the antiseptic action of the juice, which is very great, serves 

 us in good stead by protecting us very largely from the evil 

 results which would otherwise follow the introduction of 

 numerous microbes with every meal. But it is with gastric 

 juice as a digestant that we have now to deal. The first 

 observers were inclined to attribute the solvent power of 

 the juice to its acid, but as Dr. Beaumont showed in his 

 classical observations on Alexis St. Martin which have laid 

 the foundation of all our modern knowledge on digestion, 

 this could not be the case. An acid of the same strength 

 is a less powerful solvent, and therefore the gastric juice 

 must contain a special solvent principle. This Eberle 

 supposed to be the gastric mucus, a supposition easily- 

 refuted. It was Schwann who discovered this special 

 principle and called it pepsin. He gave the name albu- 

 minose to the product of its action on albumin ; Lehmann's 

 name peptone, however, has since been generally adopted. 

 Lehmann recognised that peptone is not coagulated by heat 

 as albumin is. 



The modern conception of the process of proteolytic 

 digestion in the stomach is the following : Gastric juice acts 

 on proteids in virtue of the compound between pepsin 

 and the acid which it contains. This compound may be 

 styled pepsin-hydrochloric acid. Like that of most other 

 ferments its action is a hydrating one, and similar products 

 may be obtained by other hydrating agencies, such as 



