PHYSIOLOGY OF Till. DIG] BTn I '.I 



the difference in weights the extenl to which they had become digested. 

 It was found thai when tin- appetite juice .ham feeding 



;| i the same time that £ 1 was placed directly in the Btomach, its di| 



tion was much more rapid than in discs in which it was placed in the 



stomach without the animal's knowing, ;is when In- was • p. 



Other foods having a direct stimulating effecl on th< 

 tion are meal extracts an. I, to a certain extent, milk. This effecl of d 

 extract is Interesting in connection with the practice of taking sou;, 

 a first or early stage in dining. It not only excites the appetite j>. 

 hut also serves as a dired stimulus to the gastric Becretion. 



As to the nature of the mechanism /"/ which this </<> 

 place, it was shown hy Popielski"" that the secretion still occurs r all 

 the nerves proceeding to the stomach are cut. Evidently, th< e, it 



is independent of the extrinsic nerve supply of th< is. A suit 



of his experiments Popielski concluded that the Becretion must dep< 

 on a local reflex mediated through the ner icturea present in tin- 



walls of the stomach itself. Another explanation of the result ; 

 however, in recent years been given more credence by the experimi 

 Bayliss ami starling on the influence of hormones on the 

 pancreatic juice (cf. page 425). Bdkins 10 suggested that a similar 

 process in the stomach might account for the continued 

 gastric juice. To test the possibility this investigator, after ligating the 

 cardiac sphincter in anesthetized animals, i' I a tube into the 



pyloric end of the stomach, through which he placed in the stomach 

 about 50 c.c. of physiological saline. After this had been in the stomach 



for an hour, he found that no water was absorbed, ami that it conl 

 neither hydrochloric acid nor pepsin, (in the other hand, if during the 



time the saline was in the stomach a decoction of the mucous membrane 



the pyloric end. made cither with peptone solution or with a BOlul 



dextrine, was injected intravenously in small quantil min- 



utes, the saline contained distinct quantities of hydrochloric acid and n 

 sin. Furthermore, it was found that, if the peptone solution or the dextrine 

 solution alone was injected intravenously, there was no such 

 of gastric secretion. The conclusion which Bdkins drew from 1 

 ments is to the effecl that the half-digested products of the earlier 

 of gastric digestion act on the mucous membrane of the Bton 



produce a hormone, which is then carried by the bl( 



the LMstric <_dands, upon which, like -in. it directly 



exciting effect. This hormone has l.een T 



tions of Edkins have been confirmed, and they explain \ nply fa 



gastric secretion is maintained after the cessation of the the 



