8 GASTRIC DIGESTION OF PROTEINS 



tissues is introduced subcutaneously or intravenously, secre- 

 tion of gastric juice ensues. 17 Bayliss and Starling are there- 

 fore disposed to accept the existence of a "gastric secreting ' 

 According to this view the normal secretory activity of the 

 gastric mucous membrane is to be referred to two factors : 

 the more important role is to be ascribed, of course, to the 

 nervous stimuli transmitted by the vagus nerves ; but a sec- 

 ond influence, determining the continuation of secretion long 

 after the influence of the first has ceased, is held to be ail 

 agency of chemical nature. This is believed to be a specific 

 substance generated in the pyloric mucous membrane under 

 the influence of acid, which, passing into the blood, is returned 

 to the mucous membrane of the stomach as a " hormone " or 

 chemical messenger, stimulating it to renewed secretory 

 activity. 18 Discussion of the hypothesis is postponed to the 

 following lecture in connection with the subject of the pan- 

 creatic secretin. 



Inhibition of Secretion. In addition to those influences 

 which induce secretion of gastric juice, others are known 

 which act to inhibit it, an example being manifested in the 

 failure to secrete following the introduction of fatty foods 

 into the stomach. Pawlow has shown that the inhibition in 

 such case arises rather from the duodenum than from the 

 stomach. Apparently alkalies also act to inhibit the secre- 

 tion at times by an influence arising from the intestine. 

 Attention has recently been called by clinicians to the 

 absence of free hydrochloric acid in the gastric secretion in 

 cases of disease of the gall-bladder, and to the value of this 

 phenomenon in diagnosis. 19 



Origin of Free HCl in Mucous Membrane of Stomach. 

 This brings us again to the old problem of the nature of 



* Edkins, Jour, of Physiol., 34, 133, 1906. 



18 E. H. Starling, Lectures on Recent Advances in the Physiology of Diges- 

 tion, p. 75, et seq., London, 1906; W. M. Bayliss and E. H. Starling, Ergebn. 

 d. Physiol., 5, 676-677, 1906. 



19 H. Hohlweg (Voit's Clinic at Giessen), Deutsche Arch. f. klin. Med., 

 108, 255, 1912. 



