AN'D VEGETABLES. 



them, unattached to the soil, and nourished 

 by the water in which they float. Some* 

 have characterized Animals as nourished by 

 their internal, and Vegetables by their exter- 

 nal surface, the latter having no such thing as 

 an internal stomach. This is ingenious and 

 tolerably correct; but the proofs of it must 

 fail with respect to those minute and simply- 

 constructed animals the Polypes, and the 

 lower tribes of Worms, whose feelers, put 

 forth into the water, seem scarcely different 

 from roots seeking their food in the earth, 

 and some of which may he turned inside out, 

 .like a glove, without any disturbance of their 

 ordinary functions. The most satisfactory 

 flemark I have for a long time met with on 

 this difficult subject is that of M. Mirbel, 

 in his TraitS d f Anatomic et dc Phi/siologie 

 VSgltahs\^ work I shall often have occasion 

 to quote. He observes, voi. I. p: If), " that 

 plants alone, have a power of deriving nou- 

 rishment, though not indeed exclusively, from 



* Dr. Alston, formerly professor of botany at Edin- 

 burgh. 



f Published at Paris two or three years since, in two 

 vols Svo. 



