INFLUENCE OF THE DEMAND FOR FOOD. 73 



organs of assimilation within itself, and having 

 receptacles in which it can lay in a store of 

 provisions, it may be said to be nourished from 

 within ; for it is from these interior receptacles 

 that the lacteals, or absorbing vessels, corres- 

 ponding in their office to the roots of vege- 

 tables, imbibe nourishment. Important conse- 

 quences flow from this plan of structure ; for since 

 animals are thus enabled to subsist for a certain 

 interval without needing any fresh supply, they 

 are independent of local situation, and may enjoy 

 the privilege of moving from place to place. 

 Such a power of locomotion was, indeed, abso- 

 lutely necessary to beings which have their sub- 

 sistence to seek. It is this necessity, again, 

 which calls for the continued exercise of their 

 senses, intelligence, and more active energies ; 

 and that lead, in a word, to the possession of all 

 those higher powers, which raise them so far 

 above the level of the vegetable creation. 



