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Dr. W. M. Bayliss and Prof. E. H. Starling. [Mar. 21, 



the stomach, the researches of Heidenhain, and especially of Pawlow,* 

 have shown that the secretion of the gastric juice is, in the first place, 

 controlled by the nervous system, and is excited by appetite, or by 

 reflex impulses arising in the mouth. Only later on, in gastric digestion, 

 does a secretion come on, determined, in some way or other, by the 

 presence and nature of the food in the stomach. This secondary secre- 

 tion is independent of the central nervous system ; but whether it is to 

 be looked upon as a local reflex, or as a chemical excitation, directly or 

 indirectly from the gastric contents, has not yet been determined. 

 As the strongly acid fluid containing the products of gastric digestion 

 leaves the stomach to enter the duodenum, it comes in contact with 

 two other secretions, the bile and the pancreatic juice, which are 

 secreted in such an amount that the duodenal contents become prac- 

 tically neutral. According to Pawlow, the secretion of the pancreatic 

 juice is exactly comparable to the secretion of saliva, and is effected 

 by a nervous reflex. The starting point of this reflex is the stimu- 

 lation of the duodenal mucous membrane by the chyme, or by 

 substances such as oil, ether, or oil of mustard. Not only is the 

 pancreatic juice turned out into the intestine just at the time when 

 it is required, but, according to Pawlow, the composition of the juice 

 varies according to the food, the proteolytic ferment being increased 

 by a diet of meat, while the amylolytic ferment is increased by a 

 starchy diet. This adaptation of the glandular activity was ascribed 

 by him to a species of "taste" in the mucous membrane. It was 

 imagined that the different constituents of the food excited different 

 nerve endings, which, in their turn, caused reflex activity of different 

 mechanisms in the pancreas itself. The field of these assumed reflexes 

 was considerably narrowed by the researches of Popielskif and 

 Wertheimer,| who showed that the introduction of acid into the 

 duodenum was productive of secretion even after destruction of all 

 nerve connections of the pancreas and alimentary canal with the 

 central nervous system, and even after extirpation of the sympathetic 

 ganglia of the solar plexus. It was with a view to determine the 

 mechanisms of this reflex secretion of the pancreas, as well as of the 

 adaptation of the pancreatic secretion to variations in the food of 

 the animal, that we began our researches. 



The last-named authors had also shown that the secretion occurred, 

 but in smaller quantities, if the acid was inserted in any part of the 

 small intestine, with the exception of the lower end of the ileum. It 

 was thus easy to examine the effects of the introduction of acid into a 

 loop of ileum in which all nerve connections with the pancreas, or 

 with the rest of the body, had been destroyed. This crucial experi- 



* ' Le Travail des Glandes Digestives,' Paris, 1901. 



f * Gazette Cliuique de Botkin,' 1900. 



X 'Journal de Physiologic,' vol. 3, p. 335, 1901. 



