DIGESTION 183 



attacked it, but of rather a greenish tint elsewhere, and it has 

 a peculiar odour. Several hours after feeding, the stomach is 

 found to contain a variable quantity of watery fluid discoloured 

 by the hay which is left behind, part of which may be found 

 floating on the fluid. At other times, when the stomach is 

 empty, the fluid is viscid, contains numerous gas bubbles, and 

 is of an amber or yellow tint ; this particular fluid is no doubt 

 saliva and mucin, with possibly a little bile, the result of a 

 reflux from the bowel. When oats alone have been given, the 

 contents of the stomach are found liquid, the fluid being creamy 

 in consistency and colour ; the oats are swollen, soft, and their 

 interior exposed ; towards the end of digestion the creamy fluid 

 is replaced by the frothy yellow one. With both hay and oats, 

 and also other foods, there is a peculiar sour-milk-like smell from 

 the contents of the stomach, more marked with bran and oats 

 than with hay, the latter, as previously mentioned, smelling like 

 sour tobacco. 



The reaction of the contents of the stomach is strongly acid ; 

 this acid reaction may be obtained on the cuticular as well as 

 the villous portion of the lining, and is very persistent ; the 

 cuticular membrane, even after prolonged washing, gives an 

 acid reaction. The acidity is derived entirely from the juice 

 secreted by the villous membrane of the fundus. Our observa- 

 tions on this subject do not agree with those of Ellenberger, 

 who says that during the first hour of digestion the contents of 

 the stomach may be alkaline ; acidity, he states, then commences 

 in the fundus and extends to the cardia, though for some time 

 the proportion of fundus acidity is three or four times greater 

 than that of the cardia ; in the course of five or six hours the 

 proportion of acid throughout the stomach is equal. When the 

 stomach is empty, as after a few days' starvation, its reaction 

 is neutral or alkaline. We have observed extreme alkalinity 

 towards the pylorus under these conditions, due, no doubt, to 

 the regurgitation of bile and pancreatic fluid. 



Alkalinity of the contents may be met with at the cardiac end 

 of the stomach ; in such cases it is due to the swallowed saliva, 

 and the stomach contents at this part exhibit a marked sugar 

 reaction. It is difficult to say whether this alkalinity is invari- 

 able ; in the writer's experience it has been seldom met with ; 

 but the period of digestion may be responsible, for it is easy to 

 understand that during the early period of digestion the stomach 

 acids will not have penetrated to the upper part of the stomach, 

 and in this way have neutralised the immense bulk of salivated 

 food of an alkaline reaction which is swallowed. 



The Stomach Acids. — It is not necessary here to enter into 

 any detail as to the nature of the gastric acids ; both in the 



