On the Vital Principle* i^j 



Belides the general fuppofition of an indepen- 

 dent living principle, an inference has been 

 drawn, from the fafts we have noticed, of a 

 nervous energy, independent of the brain. It may 

 therefore be proper to explain the fenfe in which 

 the uncertain term (;f nervous energy is employed 

 in this efiay, left it fhould be confounded with 

 the notion of a vital principle. By this term 

 then, I mean that condition, derived from the 

 brain, to different parts of the body, by means 

 of which they become capable of motion. In 

 this definition I allude to no theory refpefting 

 the nature of the foul, nor refpefting the fpeci- 

 fic nature of the nervous energy, but confine 

 the ternris to fafts. The proof of the definition 

 will appear, from the arguments I am going to 

 mem! "in. 



To fhew, by direct proof, that there is no 

 indepentlent vital principle, I would obferve, 



I. That it is juftly urged by Dr. Monro* 

 againft the doftrine of the vis infita, that there 

 is too much defign in the aftions of different 

 mufcles, affefted by different ftimuli, to be the 

 effe(fl of mere mechanifm. This argument is 

 ftrongly againft the exiftence of a vital principle. 

 Thus, when the hand or foot is burnt, or other- 

 wife fuddenly inJOTrd, the mufcles on the part 

 immediately ftinwlated are not thrown into 



* Obfervaiions on the Ncrv. Syft. p. 95 to 99. 



adtion. 



