4 GASTRIC DIGESTION OF PROTEINS 



' ' little stomach. ' ' By simply cutting out of the gastric wall 

 a section, closing the wound in the stomach and stitching the 

 blind sac constructed from the exsected patch into the ab- 

 dominal wound, a "ventriculus" is formed, which during 

 digestion secretes coincidently with the stomach itself. In 

 the older method, however, the secretory nerves are divided 

 and the secretory conditions are therefore by no means 

 normal. Pawlow corrected this fault in his method of oper- 

 ating, by freeing completely only the mucous membrane of 

 the patch and sparing a pedicle of the serous and muscular 

 coats in attachment with the stomach proper, so that the 

 vagus fibres going to the mucosa may pass from the wall of 

 the large stomach to that of the small stomach by route of 

 the pedicle. He has been able to show that the vagus nerve 

 actually conducts secretory impulses to the stomach by the 

 following methods. If both vagi are excluded, either by 

 section or by atropine, the usual result of the "mock meal" 

 fails to appear; by stimulation of a peripheral vagus seg- 

 ment gastric secretion can be induced, provided stimulation 

 is not practiced immediately after the section but preferably 

 after sufficient time has elapsed for the degeneration of the 

 vagus cardiac fibres. 



Nervous Mechanism of Secretion. Efficient secretory 

 stimulus, passing from the cortex of the brain by way 

 of the vagus nerves to the stomach, producing in case of 

 the "mock meal" experiment a full complement of active 

 gastric juice, fails after section of the vagi; but after a 

 time a certain amount of gastric adaptation takes place 

 whereby a continuous secretion is maintained sufficient 

 for the digestive requirements. 2 Bickel has observed con- 

 tinuous secretion of normal gastric juice in the nerveless 

 stomach in a dog in which he cut all the extra gastric nerves 

 of a gastric diverticulum. 3 



8 P. Katschowsky (Pawlow's Laboratory), Pfluger's Arch., 84, 6, 1901. 



A. Bickel, Deutsche med. Wochenschr., 1909, 704. Literature on the 

 neuro- secretory mechanism of gastric secretion : A. Bickel, Handb. d. Biochemie, 

 3', 58-63, 1910. 



