SECTION III 

 DIGESTION IN THE STOMACH 



GASTRIC JUICE 



WITHIN five minutes of the taking of food into the mouth a secretion 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 accumu- 

 lates 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 continued 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-stuffs. 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 occluded by the cicatrisation of the ulcer pro- 

 duced. In order to preserve the individual from starvation, it was neces- 

 sary to perform gastrostomy, i.e. to make an artificial opening into the 

 stomach through which he could be fed. Although in this patient the pas- 

 sage of the saliva from mouth to stomach was completely prevented, it was 

 observed that merely taking food into the mouth was followed by the secre- 

 tion 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 eat also 

 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 collected in vessels connected with 

 the fistulous opening. If taken from a fasting animal, such a juice is per- 

 fectly free from admixture, and can be regarded as pure gastric juice. It 

 is quite clear, strongly acid, without smell. It contains about 0-3 to 0-6 per 



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