GASTRIC JUICE. 217 



from the columnar cells at the sides, leaving a small central 



Three observers, Middeldorph, Briicke, and Kolliker, 

 almost simultaneously, each one ignorant of the observations 

 of the others, noted in the submucous tissue the presence of 

 a few involuntary muscular fibres surrounding the ccecal 

 extremities of the stomach-tubes. 8 These are supposed to be 

 active in discharging the contents of these tubes during the 

 secretion of the gastric juice. 



Closed Follicles. In the substance of the mucous mem- 

 brane, between the tubes and near their coecal extremities, are 

 occasionally found closed follicles, like the solitary glands 

 and patches of Peyer of the intestines. These are not 

 always present in the adult, but are generally found in 

 children. They are usually most abundant over the 

 greater curvature, though they may be found in other situa- 

 tions. In their anatomy they are identical with the closed 

 follicles of the intestines, and do not demand special consid- 

 eration in this connection. 



Gastric Juice. 



At the present day it seems profitless to argue the ques- 

 tion of the existence of a digestive fluid in the stomach ; and 

 the discussions of the earlier physiologists as regards the 

 possibility of the existence of a fluid capable of dissolving the 

 articles of food have only an historical interest. It is im- 

 portant, however, to follow the experiments by which the 

 existence and the properties of the gastric juice were brought 

 to light, as the discovery of this fluid marks the commence- 

 ment of our definite knowledge concerning the process of 

 digestion. 



In 1752, while the controversy between those who be- 

 lieved that the stomach simply triturated the food, and 



1 Op. dt. 



a LONGET, Traite dc Physiologic, Paris, 1861, tome i., p. 180. 



