SECRETION. 239 



esis, especially that part connecting the border-cells with the formation of 

 HO, can only be accepted provisionally until further investigation confirms 

 or disproves it. It should be stated that the alkalinity of the secretion obtained 

 from the pyloric glands by Heideuhain's method has been attributed by some 

 authors to the abnormal conditions prevailing, especially to the section of the 

 vagus fibres that necessarily results from the operation. Contejean l asserts 

 that the reaction of the pyloric membrane under normal conditions is acid in 

 spite of the absence of border-cells. 



Influence of the Nerves upon the Gastric Secretion. — It has been very 

 difficult to obtain direct evidence of the existence of extrinsic secretory nerves 

 to the gastric glands. In the hands of most experimenters, stimulation of the 

 vagi and of the sympathetics has given negative results, and, on the other 

 hand, section of these nerves does not seem to prevent entirely the formation of 

 the gastric secretion. There are on record, however, a number of observations 

 that point to a direct influence of the central nervous system on the secre- 

 tion. Thus Bidder and Schmidt found that in a hungry dog with a gastric 

 fistula (page 288) the mere sight of food caused a flow of gastric juice ; and 

 Richet reports a case of a man in whom the oesophagus was completely oc- 

 cluded and in whom a gastric fistula was established by surgical operation. 

 It was then found that savory foods chewed in the mouth produced a marked 

 flow of gastric juice. There would seem to be no clear way of explaining the 

 secretions in these cases except upon the supposition that they were caused bv a 

 reflex stimulation of the gastric mucous membrane through the central nervous 

 system. These cases are strongly supported by some recent experimental 

 work on dogs by Pawlow 2 and Schumowa-Simanowskaja. These observers 

 used dogs in which a gastric fistula had been established, and in which, more- 

 over, the oesophagus had been divided in the neck and the upper and lower 

 cut surfaces brought to the skin and sutured so as to make two fistulous 

 openings. In these animals, therefore, food taken into the mouth and subse- 

 quently swallowed escaped to the exterior through the upper (esophageal 

 fistula, without entering the stomach. Nevertheless this "fictitious meal," 

 as the authors designate it, brought about a secretion of gastric juice. If in 

 such animals the two vagi were cut, the "fictitious meal" no longer caused 

 a secretion of the gastric juice, and this fact may be considered as showing 

 that the secretion obtained when the vagi were intact -was due to a reflex 

 stimulation of the stomach through these nerves. In later experiments 8 from 

 the same laboratory the secretion caused in this way bv the act of eating is 

 designated as a " psychical secretion," on the assumption, for which consider- 

 able evidence is given, that the reflex must involve psychical factors such as 

 the sensations accompanying the provocation and gratification of the appetite. 

 In favorable cases the fictitious feeding was continued for as long as five to 

 six hours, with the production of a secretion of about 700 c.e. of pure gastric 



1 Archives de Physiologie, 1S9'J, p. 554. 



* Du Bois-Reymond! & Archivjur Physiologic, 1895, S. 53. 



1 Die Arbeit der Verdauungsdriisen, Wiesbaden, 1898. 



