118 STUDIES IN CLINICAL PHYSIOLOGY 



when pain is being caused by strong gastric peristalsis 

 against a spasmodically closed pylorus it provides a 

 safety-valve. The beneficial effect on ulcers and 

 hffimatemesis is probably due to the withdrawal of 

 the acid and the prevention of distention. 



Feeding after Gastrostomy. — Pawlow's experi- 

 ments, above referred to, give a valuable hint as 

 to the feeding of patients who are unable to swallow 

 and have suffered a gastrostomy. It is well known 

 that they may fail to make progress even when the 

 operation has apparently not been postponed too long. 

 Sometimes they will request that they should still 

 be allowed to take food into the mouth " just to 

 taste it." Evidently they lack the first secretion of 

 gastric juice due to the reUsh with which the food is 

 tasted and swallowed, and digestion may in conse- 

 quence be very imperfect. This may be overcome 

 by the simple device of adding some form of extrac- 

 tives to the feed, such as beef-tea, gravy, soup, or a 

 meat essence. Thus the chemical mechanism is 

 brought into play though the nervous reflex fails. 

 Excellent practical results have been obtained by 

 this expedient. 



THE SECRETION OF PANCREATIC JUICE. 



This was first thought by Pawlow to be due to a 

 reflex through the vagus, but it has been shown by 

 Bayliss and Starhng that the stimulus is in reality 

 chemical, though it is not impossible that a secretion 

 can also be induced by the vagus. When the hydro- 

 chloric acid of the gastric juice touches the mucous 



