RECEPTACLES OF FOOD. 63 



into blood ; a fluid which, like the returning sap 

 of plants, consists of nutriment in its completely 

 assimilated state. It will be necessary, therefore, 

 to enter into a more particular examination of the 

 objects of these different processes. 



In the more perfect structures belonging to the 

 higher orders of animals, contrivances must be 

 adopted and organs provided for seizing the appro- 

 priate food, and conveying it to the mouth. A 

 mechanical apparatus must there be placed for 

 effecting that minute subdivision, which is neces- 

 sary to prepare it for the action of the chemical 

 agents to which it is afterwards to be subjected. 

 From the mouth, after it has been sufficiently mas- 

 ticated, and softened by fluid secretions prepared 

 by neighbouring glands, the food must be conveyed 

 into an interior cavity, called the Stomach, where, 

 as in a chemical laboratory, it is made to undergo 

 the particular change which results from the 

 operation termed Digestion. The digested food 

 must thence be conducted into other chambers, 

 composing the intestinal tube, where it is con- 

 verted into Chyle, which is a milky fluid, con- 

 sisting wholly of nutritious matter. Vessels are 

 then provided, which, like the roots of plants, drink 

 up this prepared fluid, and convey it to other 

 cavities, capable of imparting to it a powerful im- 

 pulsive force, and of distributing it through appro- 

 priate channels of circulation, not only to the res- 

 piratory organs, where its elaboration is completed 

 by the influence of atmospheric air, but also to all 

 other parts of the system, where such a supply is 

 required for their maintenance in the living state. 

 The objects of these subsequent functions, many 



