ABSORPTION. 91 



necessary aliment. These senses and organs appear to be 

 gradually superadded to the simple digestive cavity which 

 constitutes the entire organism of the lowest animal. The 

 organic apparatus for the prehension and preparation of the 

 food prior to its introduction into the interior of the diges- 

 tive cavity, becomes more complicated as we ascend in the 

 scale of organization. 



The organs of prehension and preparation are most ad- 

 mirably adapted to the peculiar food, habits, and instincts 

 of each animal. In man, whose wants are infinitely more 

 numerous, these organs exist in the highest condition of 

 development. He is provided with a hand, which may be 

 justly regarded as the most perfect of prehensible instru- 

 ments. To the skillful use of this organ, under the guid- 

 ance of reason, he owes his superiority over the other 

 animals, whose anterior members are organized more for 



Fig. 23. 



the support of their bodies than for the seizure of objects. 

 The other organs consist of an alimentary tube or canal 



