EVOLUTION OF LIFE. 57 



extends over the surface of their system, simi- 

 lar to vegetables ; insomuch, that when the 

 whole is cut into parts, each portion possesses, 

 within itself, the power of generation and nutri- 

 tion. 



As we ascend in the scale of animals, we are 

 able to distinguish, between different classes of 

 each, a considerable degree of difference in the 

 organisation of which they are composed. Their 

 digestive organs, instead of being dispersed 

 over the whole external surface of their frame, 

 have a particular organ to which this office is 

 especially allotted ; while vegetables, in gene- 

 ral, act upon the fluid matter by which they 

 are surrounded, and convert it into nourish- 

 ment; animals, in general, on the contrary, 

 select it by means of the organs of sense, with 

 which they are supplied. Such, indeed, is the 

 absolute magnitude of the organs of sense in 

 these beings, that they can be easily de* 

 tected : the caterpillar has six eyes on each 

 side, and in the snail five eyes are distinctly 

 visible at the extremity of each of its horns, 

 exclusive of which, a number of fibrils arise 

 from its mouth, without doubt, imparting to 

 the sense of taste, an exquisite degree of sensi- 

 bility. 



In the bee, the eyes are not only of a very 

 large size, but owing to- the peculiarity io their 

 construction, the area of their surface becomes 



