The Digestion of Food 



105 



forces it backwards between the pillars of the fauces into 

 the pharynx. There is only one pathway for the food to 

 travel, and that is down the oesophagus. 



The slow descent of the food may be seen if a horse or 

 dog be watched while swallowing. Even liquids do not fall 

 or flow down the food passage. Hence it is that acrobats 

 are able to drink while standing on their heads, and that 

 a horse drinks with his mouth below the level of the 

 stomach. The food is under the control of the will until 

 it has entered the pharynx ; all the 

 later movements are involuntary. 



Experiment 44. Place the fingers on 

 the " Adam's apple." Pretend to swallow 

 something, and you can feel the upper 

 part of the windpipe and get a very fair 

 idea of the action of the epiglottis and the 

 closing of its lid, thus covering the entrance 

 and preventing the passage of food into the 

 windpipe. 



159. The Stomach. The stomach 



is the most dilated portion of the FIG. 49. Section of Face, 

 alimentary canal and-ihc piiucipal (Showing the parotid and 



c , . . T r submaxillary glands.) 



organ o -digest-ton. Its form is not 



easily described. It has been compared to a bagpipe, 

 which it resembles somewhat when moderately distended 

 (Fig. 52). 



We may describe the stomach as a pear-shaped bag, with 

 a capacity of about four pints. It lies chiefly on the left 

 side of the abdomen, under the diaphragm, and protected 

 by the lower ribs. 



The orifice by which the food enters the stomach is called 

 the cardiac opening, because it is near the heart. The open- 

 ing by which the food leaves the stomach and where the 



