DIGESTION. 



only in small quantities ; but in the organ filled with food, 

 especially if solid, the gastric juice is secreted in abundance. 

 Its acid properties are always well marked. 



Liver. Pylorus. Gullet. Pancreas. Stomach. 



Gall Bladder. 



Spleen. 



Colon. 



Small 

 'Intestine. 



""Colon. 



Small Intestine. 



Eectum. 



Fig. 24. Digestive Apparatus in Man. 



63. The alimentary substances which accumulate in the 

 stomach being pressed on by the muscular wall of the stomach 

 and abdomen would reascend the gullet, but are prevented by 

 the contraction of this organ. This resistance, however, is fre- 

 quently overcome, as in regurgitation and vomiting. On the 

 other hand, the contraction of the pylorus during digestion 

 retains the food for some time in the stomach. 



