SECTION 111 

 DIGESTION IN THE STOMACH 



GASTRIC JUICE 



WITHIN five minutes of the taking of food into the mouth a secre- 

 tion of gastric juice begins from the multitude of tubular glands 

 which make up the greater part of the mucous membrane of the 

 stomach. As the food, masticated and thoroughly mixed with 

 saliva, is swallowed in successive portions, it accumulates in a mass 

 in the fundus of the stomach, and the mass thus formed is penetrated 

 with difficulty by the juice which is continually being poured out 

 by the walls of the stomach, so that salivary digestion can be con- 

 tinued for a considerable time. 



The gastric juice, which is so poured out, can be obtained in 

 various ways, most of them yielding it mixed more or less with the 

 food-stufis. In clinical practice it is the custom to give a definite 

 meal, and then at a given interval after the meal to wash out the 

 stomach, so obtaining a mixture of gastric juice and partially digested 

 food. 



A method of obtaining the juice in a perfectly pure condition 

 has been devised by Pawlow. A case had been previously described 

 by Richet in which, as the result of the accidental taking of a corrosive 

 alkali, the oesophagus had become completely occluded by the cica- 

 trisation of the ulcer produced. In order to preserve the individual 

 from starvation, it was necessary to perform gastrostorny, i.e. to make 

 an artificial opening into the stomach through which he could be 

 fed. Although in this patient the passage of the saliva from mouth 

 to stomach was completely prevented, it was observed that merely 

 taking food into the mouth was followed by the secretion of gastric 

 juice. Pawlow produced this condition artificially in dogs. The 

 oesophagus was divided and the two ends brought to the surface 

 of the neck. At the same time an opening was made into the stomach. 

 The animals could be fed either through the opening of the oesophagus 

 in the neck, or with solid food through the gastric fistula. They 

 could also eat and swallow food as usual, but the food thus swallowed 

 simply fell out of the opening in the neck without passing into the 

 stomach. Under these circumstances it is found that the taking of 

 food is quickly followed by a secretion of gastric juice, which can be 



766 



