96 HUMAN PHYSIOLOGY. 



peristaltic in character, which serve not only to incorporate the gastric juice 

 with the food, but also serve to eject the liquefied portions of the food into 

 the intestine. 



After the entrance of the food both the cardiac and pyloric orifices are 

 closed by the contraction of their sphincters. Within five minutes (in the 

 cat) annular constrictions begin in the pyloric region which move peristaltic- 

 ally towards the pylorus. As digestion proceeds these constrictions or con- 

 tractions become more frequent and more vigorous. The result is a tritura- 

 tion and liquefaction of the food. So soon as it is liquefied the pylorus 

 relaxes and permits of its discharge into the intestine. The pylorus then 

 closes and further preparation of food goes on. From time to time the py- 

 lorus relaxes to permit the discharge of prepared and liquefied food until 

 digestion is completed. The reason assigned for the relaxation of the 

 sphincter muscle is the presence of a sufficient amount of free hydrochloric 

 acid on the gastric side. The reason assigned for its contraction after the 

 discharge of food into the duodenum is the presence of the hydrochloric acid 

 in this region. With its neutralization by the alkalies there present its influence 

 in causing contraction of the sphincter gradually diminishes. In the cardiac 

 region there is an absence of peristalsis though the muscle wall is in a state 

 of active tone. The fundus acts as a reservoir for food and delivers its 

 contents to the pyloric region as rapidly as it is ready to receive them. 



TABLE SHOWING DIGESTIBILITY OF VARIOUS ARTICLES OF FOOD. 



Hours. Minutes. 



Eggs, whipped i 20 



Eggs, soft-boiled 3 



Eggs, hard-boiled 3 30 



Oysters, raw 2 55 



Oysters, stewed 3 30 



Lamb, broiled 2 30 



Veal, broiled 4 



Pork, roasted 5 15 



Beefsteak, broiled 3 



Turkey, roasted .' . 2 25 



Chicken, boiled 4 



Chicken, fricasseed 2 45 



Duck, roasted 4 



Soup, barley, boiled ' i 30 



Soup, bean, boiled 3 



Soup, chicken, boiled 3 



Soup, mutton, boiled 3 30 



