XVI.] STOMACH. GASTRIC JUICE. MILK. 171 



from the upper part of the oesophagus show 

 no unstriped fibres. 



b. The submucous tissue contains small serous 

 and mucous glands (cf. Lesson xv.). Each of 

 these consists of a duct, dividing and ending 

 in dilatations, the alveoli. 



c. Traces of the muscularis mucosas. 



d. The papillae of the mucous membrane. 



e. The epithelium forming a layer several cells 

 deep, the deeper being columnar or sphe- 

 roidal, the superficial cells flattened (cf. Epi- 

 dermis, Lesson xxiv.). 



C. GASTRIC JUICE. 



1. Artificial Gastric Juice. 



a. Tear off the mucous membrane from the 

 stomach of a mammal, cutting away the 

 pyloric region (the stomach of a pig obtained 

 from the butcher's will serve). Mince it 

 finely. Put it in a flask with two hundred 

 times its bulk of hydrochloric acid *2 p.c., 

 and place the flask in a water bath at about 

 40 C. After some hours a considerable part 

 will be dissolved. Decant, and filter the 

 decanted fluid. A solution of pepsin in 

 hydrochloric acid will be obtained; it will, 

 however, contain a considerable quantity of 

 peptone. 



b. Mince another gastric mucous membrane; 



