COMPLEX APPARATUS FOR NUTRITION. 



81 



uniform distribution of the nutritious fluids elaborated by 

 the organs of digestion. This separation of functions, again, 

 leads to the introduction of another system of canals or ves- 

 sels, for transmitting the fluids from the organs which pre- 

 pare them to the heart, as into a general reservoir. In the 

 higher orders of the animal kingdom, all these processes are 

 again subdivided and varied, according to the species of food, 

 the habits and mode of life, assigned by nature to each in- 

 dividual species- For the purpose of conveying clearer no-, 

 tions of the arrangement of this extensive system of vital 

 organs, I have drawn the annexed plan (Fig. 265,) which 



265 



exhibits them in their natural order of connexion, and as 

 they might be supposed to appear in a side view of the in- 

 terior of a quadruped. To this diagram I shall make fre- 

 quent reference in the following description of this sys- 

 tem. 



The food is, in the first place, prepared for digestion by 

 several mechanical operations, which loosen its texture and 

 destroy its cohesion. It is torn asunder and broken down 

 by the action of the jaws and of the teeth; and it is, at the 

 same time, softened by an admixture with the fluid secre- 

 tions of the mouth. It is then collected into a mass, by the 

 action of the muscles of the cheek and tongue, and swal- 



VOL. II. 



11 



