GASTRIC JUICE AXD CHANGES IN STOMACH. 169 



much more easily followed and measured than the proteolytic, 

 the ferment strength is frequently determined by observing 

 the extent of the coagulating power. The test may be made 

 in a number of ways and has already found clinical application, 

 but the real value of the process remains to be demonstrated. 



PRODUCTS OF PEPTIC DIGESTION. 



Frequent reference has already been made to the question 

 of what is produced from the food proteins during peptic di- 

 gestion. In answering this question it is necessary to distin- 

 guish between what may be formed under the influence of 

 pepsin and hydrochloric acid, with sufficiently long time af- 

 forded for the action, and what actually is formed in the few 

 hours in which food, under normal conditions, remains in the 

 stomach. On this subject the views of physiological chemists 

 have undergone various and marked changes. The stomach 

 has long been considered, popularly, as the chief organ of 

 digestion, and this view appeared to be confirmed by the results 

 of the earlier experiments carried out with artificial digestive 

 mixtures. The gradual disappearance of coagulated egg albu- 

 min or of fibrin, with the simultaneous formation of soluble 

 products, is a phenomenon easily observed. Various precipi- 

 tation reactions served to recover from the mixture the prod- 

 ucts formed and these were early spoken of as " peptones." 



At this time, however, the distinction between real peptones 

 and proteoses was not thought of. It remained to be shown 

 that all this abundant mass of material formed in the course of 

 a few hours' digestion consists actually in the main of prod- 

 ucts preliminary to peptones. This later knowledge came 

 somewhat slowly and led to a radical view of just the opposite 

 order from the early popular one of the function and impor- 

 tance of the stomach. If the stomach is not the principal 

 organ of digestion, it was asked, what is its real value? If 

 the operations carried out there may be accomplished as well 

 later in the intestine, if its work is wholly preliminary and if 

 in turn these preliminary stages are not really essential, what 

 are the functions for which the presence of the stomach ap- 

 pears to be "practically" necessary? A number of remark- 



