ORGANS OF THE MAMMALIA. 



103 



And so in its turn, the process of digestion would cease 

 with the want of action in the heart and brain, so that all 

 these functions are performed, as it were, in a circle, each 

 one being dependant on the other. In one view, each of 

 these functions may be considered as subservient to the 

 other, while in another view, each is seen to be entirely 

 dependant on the other. 



294. Plan of the most important Viscera. A connect- 

 ed view of the most important visceral, and vital organs, 

 are represented by Fig, 74. This is a side view, showing 



Fig. 74. 



the natural situation of the parts, as they are placed in 

 quadrupeds, but may be considered as applying to the hu- 

 man species without any material change. 



295. In the explanation of this view we will begin with 

 the passage of the food to the stomach. The esophagus, o, 

 is a muscular tube leading from the mouth to the stomach, 

 and through which the food passes to the latter organ. Of 

 the stomach, s c, is the part nearest the heart, and is called 

 the cardia, or cardiac portion, while the opposite part is 

 termed pylorus. This leads to the intestinal tube marked 

 i, i. The mesentery, in, connects the latter part with the 

 back ; the use of which will be explained directly. The 

 enlargement, r, is the receptacle of the chyle , and from 



