INFLUENCE OF NERVOUS SYSTEM ON DIGESTIVE GLANDS 403 



rosa 

 cularis 



Pawlow also performed the converse experiment. In dogs in 

 which a pouch had been isolated from the stomach and made to 

 open to the exterior by the surgical procedure illustrated in Figs. 161 

 and 162, he introduced into the large stomach, without the animal's 

 knowledge, food of various kinds. This is best done in a sleeping 

 dog. The secretion of gastric juice, both in the main stomach and 

 in the pouch or miniature stomach", which is known in a great 

 variety of conditions to present an exact picture of the process of 

 secretion in the large, is markedly delayed and scanty when it does 

 appear. Bread and coagulated egg-white did not yield a single 

 drop during 

 the first hour 

 or more. Raw 

 flesh excited a 

 secretion, but 

 after an inter- 

 val of fifteen 

 to forty - five 

 minutes, in- 

 stead of five 

 or six to ten, 

 as in sham 

 feeding. It was 

 very scanty 

 during the 

 first hour 

 (only o n e - 

 third the nor- 

 mal amount), 

 and possessed 

 a very low di- 

 gestive power. 

 The impor- 

 tance of the 

 psychical ele- 

 ment is shown by the fact that in one dog, which, after a weighed 

 amount of meat had been introduced into its stomach (without its 

 knowledge), received a sham meal of meat, the amount of protein 

 digested after one and a half hours was five times greater than in 

 another animal treated exactly in the same way, except that the sham 

 meal was omitted. But even after division of the vagi, gastric secre- 

 tion is still caused by the introduction of various substances into the 

 stomach, especially water and meat extract. The active substances 

 in the meat extract are, for the most part, insoluble in alcohol. 

 Kreatin is inactive. It is in virtue of these substances that raw 

 meat placed directly in the stomach causes some secretion after a 



Fig. 162. Pawlow's Stomach Pouch. S, the completed pouch; 

 V, cavity of stomach. 



