PHYSIOLOGY "i i 111 DIG] 3TTV1 01 



the main function of the stomach is to crush or triturate t. :■ to 



act on it chemically. Ti t French sciential Reaumur and a little 



later the Italian Abbe* Spallanzani L729-179 icked this problem by 



methods that anticipate those of Rehfuss and Einhorn. Spallanzani ulti- 

 mately devised the method of swallowing small perforated wooden tu 

 containing foodstuffs and covered by small linen bags. After the i 

 were passed per rectum, he found that considerab iion or digestion 



of the food had occurred, bul that the wooden tubes, h< r thin- 



walled they might be, were qo1 crushed. In order to secure sam] 

 the gastric juice free from fund, the only method available to the older 

 investigators consisted in swallowing sponges attached to threads, which 

 after being for some time in the Stomach were withdrawn and 

 dry of juice. 



The next great contribution came from this country, where, In 18 

 \)v. Beaumont, while a surgeon in the service of the American troops 

 located at Mackinaw, made observations on a Canadian voyageur by the 



name of Alexis St. Martin, who by the premature disci gun 



had wounded himself in the stomach, the wound never healing but le 

 ing a permanent gastric fistula. Beaumont arranged to keep Alexis Si 

 Martin in his service for several years, during which time he made 

 numerous observations on the process of digestion in tl h — 



observations many of which are of great value oven at the pr< lay. 



By none of these methods, however, could a sample of pUT trie 



juice be secured while the digestive process was actually in pi 

 To make the collection of such a sample possible, Eeidenhain devised a 

 method of isolating portions of the stomach wall as pouc pening 



through fistula on the abdominal wall. The results of Heidenhain'a 

 experiments are, however open to the objection that the I ion in 



the isolated pouches may not really correspond to thi irring in 



main stomach, s'n the connections of the pouches with tl 



nervous system must have been Si In order that tl 



tions might remain as nearly intact as possible, the Russian ph; 

 Pavlov, 1 devised an ingenious operation in which the pouch, or "minia- 

 ture stomach," remains coi n< cted with the main stomach tl 



siderable width of mUCOUS and submucous tissue and in which tl 



connections arc not severed. Th< ntial nature <<( tl 



will be evident from the accompanying diagram. Fig 148 



The most leeent i u \ est i ga 1 ions have been made DJ I 

 Carlson.'' The former fed animals food impregnated with bismuth sub- 

 nitrate. and then exposed the animal to the JC-rays \ - 



produced by the food mass in tl •lach, and from I in the 



outline «.f this shadow facts have been collect - the 



