S ECT. V. DEFINITION OF THE PLANT. 



to be founded ; and in the next place, as we are 

 possessed of no criterion by which we may infallibly 

 judge of the existence of the faculty of sensation, 

 the difficulty of decision remains the same as before. 

 For if I should happen to meet with an animal which 

 does not exhibit what I might be inclined to regard 

 as a satisfactory evidence of sensation, I must of 

 necessity arrange it in the class of vegetables, while 

 at the same time it still remains an animal. 



M. Bonnet, of Geneva, defined the plant to be an Of Bon- 

 organized body nourished by means of roots placed net " 

 externally ; the animal being just the converse 

 that is, an organized body nourished by means of 

 roots placed internally, namely, the lacteals of the 

 animal system. This definition is sufficiently ap- 

 plicable to the generality of cases, but it fails just 

 where the foregoing definitions have been found to 

 fail that is, in cases which are really doubtful. And 

 if this criterion is the only true test of distinction 

 between the animal and vegetable, then all animals" 

 whatever before they are protruded from the egg or 

 womb are to be regarded as plants ; because they 

 are then nourished by means of an umbilicus, which 

 we cannot but regard as an external root. 



Dissatisfied with all previous distinctions, and Of Hed- 

 qualified from the depth of his knowledge and ex- Wlg " 

 tent of his views to mark and select the most de- 

 cisive characters of discrimination, the acute and in- 

 defatigable Hedwig suggested the following rule, 

 founded as he thought on a universaj law of vege- 



