140 Dr. Penhal on the 



noticed with admiration, as exhibiting the moft 

 obvious figns of perceptivity. And if we ad- 

 mit fuch motions, as criteria of a like power, 

 in other beings, to attribute them, in this in- 

 ftance, to mere mcchanifm, aduated folely by 

 external impulfe, is to deviate from the foundeft 

 rule of philofophizing, which directs us not to 

 multiply caufes, when the effeds appear to be 

 the fame. Neither will the laws of eleftricity 

 better folve the phenomena of this animated 

 vegetable: For its leaves are equally afFeded by 

 the contaft of eledric, and non-eleftric bodies » 

 ihew no change in their fenfibility, whether the 

 atmofphere be dry or moift ; ajid inftantly clofe 

 when the vapour of volatile alkali, or the fumes 

 of burning fulphur are applied to them. The 

 powers of chemical ftimuli, to produce contrac- 

 tions in the fibres of this planf, may perhaps 

 lead fome philofophers, to refer them to the 

 vis infiia, or irritability, which they afTign to cer- 

 tain parts of organized matter, totally diftinft 

 from, and independent of, any fentient energy,' 

 But the hypothefis is evidently a folecifm, and 

 refutes itfelf. For the prefence of irritability 

 can only be proved by the experience of irrita- 

 tions, and the idea of irritation involves in it that; 

 of feeling. 



But there is a fpecies of the order of Decandria, 

 which cor.ftantly and uniformly exerts a felf- 

 moving power, uninfluenced either by chemical 

 ftim.ulj, or by any external impulfe v/hatfoever. 



This 



