SECT. V. DEFINITION OF THE PLANT. 471 



was not yet introduced : * but it was made in the very 

 terms of the division by M. Bonnet, in his Consi- 

 derations sur les Corps Organises; and by Fourcroy, 

 in his Systeme des Conaissances Chimiques,-}- who 

 regards it as affording the best criterion for dis- 

 tinguishing the mineral from the plant. But M. 

 Mirbel seems to have been the first who has adopted 

 it as affording a universal criterion for distinguish- 

 ing the plant from the animal, and it seems to have 

 already obtained a preference even with some of the 

 best judges, though it does not yet appear to have been 

 very scrupulously put to the test.^ Is it true that the 

 Lumbricus terrestris feeds only on earthy as has been 

 generally supposed, or does it feed also on roots ? 

 What is the food of leeches and minnows, which have 

 been known to live for years merely in pure water ? 

 And what is the food of zoophytes in general? 

 Till these questions are satisfactorily answered the 

 criterion cannot be deemed infallible. Regarding 

 it, however, as the best ground of distinction that 

 has hitherto been suggested, I deduce from it the 

 following definition of the vegetable and animal : 

 A vegetable is an organized and living substance 

 springing from a seed or gem, which it again pro- 

 duces ; and effecting the developement of its parts 

 by means of the intro-susception and assimilation of 



* Videmus enim herbas et plantas, ex terra et aqua nutriri; 

 animalia vero, ex herbis et fructibus. De Aug. Scien. 1. iv. 

 + Smith's Introduction, chap. i. 

 I Tome vii. p. 34. 



