THE FUNCTIONS OF THE DIGESTIVE ORGANS. 505 



ferments may perhaps have a zymogen state of existence which requires 

 an activator to bring its action into play. Every cell may possess several 

 ferments. One substance may serve to activate a given ferment, while 

 another activates a different one. Again, the gland-cells act by the aid 

 of ferments. They are broken down and again built up until from the 

 building material, which is of quite different composition, the specific 

 secretion is produced. Now the cells of the glands in the stomach produce 

 the secretion during a period of rest. They retain it until, by means of 

 some sort of stimulation, they are made to give it up. We must not 

 imagine that the act of secretion itself is a purely physical process. The 

 material of which the secretion is composed does not exist in the cells in 

 a condition capable of exerting the characteristic function. Probably 

 during the secretion activity, a group of atoms is eliminated here and 

 there and new combinations are effected. We do not yet know whether 

 all these cells of a gland contain the same secretion, or not. All such 

 assumptions are but speculations, without any experimental foundation. 

 We mention them merely because the first glance at the results of Paw- 

 low's investigations, which almost lead one to assume that the digestive 

 glands are furnished with intelligence, must give one the impression that 

 we are meeting with conditions here which are infinitely complicated, and 

 which will be, apparently, inaccessible to further investigation. This is 

 not really true. We have no doubt that from these experiments of Paw- 

 low the first light will be shed upon the great obscurity which enshrouds 

 the functions of the glands and their dependence upon nervous influences. 

 To be sure, we are still far from the goal. Pawlow deserves our thanks 

 for having at least pointed out to us the way this is to be attained. 



We have up to now been concerned chiefly with pepsin, which is brought 

 into activity by acid, and which is extremely sensitive to alkali. Now it 

 is known that the pylorus part of the stomach secretes no acid. In spite 

 of this fact, there is digestive power in the juice produced at this region 

 of the stomach, as has been shown by experiments with an isolated blind 

 sack in the pylorus. It is of much interest to find by the experiments of 

 Pawlow and Parastschuk * that the proteolytic ferment of the pylorus 

 digestive juice also requires hydrochloric acid to activate it. The acti- 

 vated juice shows a proteolytic and milk-coagulating action. It has been 

 asserted that the pylorus portion of the stomach secretes a ferment which 

 is active in alkaline solution. 2 If this be true, then we shall be forced to 

 assume that a ferment other than pepsin is produced in this portion of the 

 stomach. At present, however, we do not have sufficient ground for believ- 

 ing that there is actually a different ferment here, for it seems far more 

 probable that the mucous membrane of the pyloric region, or the glands 



1 Z. physiol. Chem. 42, 415 (1904). 



2 Karl Glassner: Hofmeister's Beitr. 1, 24 (1904). 



