xlii INTRODUCTION. 



in motion, they evidently do not impart it. 

 The seed of a vegetable, or the egg of a bird 

 have each of them, if I may so speak, a 

 punctum saliens, a radiating principle, which, 

 under certain circumstances, they can retain 

 in a latent state, for a considerable time ; but 

 if once that principle is extinct, no application 

 of heat, or electricity, under any form, can 

 revive it, so as to commence any develope- 

 ment of the germe it animated. Experiments 

 have been made upon human bodies ; and 

 those of other animals, which, by the applica- 

 tion of galvanism, after death, have exhibited 

 various muscular movements, such as lifting 

 the eye-lids, moving the arms and legs, &c. 

 but though motions usually produced by the 

 will acting by the nerves upon the muscles 

 have thus been generated by a species of the 

 electric fluid, proving its affinity with the 

 nervous power or fluid, yet the subjects of the 

 experiment, when the action was intermitted, 

 continued still without life ; no return of that 

 power or essence which was fled for ever, 

 being effected by it,- which seems to render 

 it clear that neither caloric nor electricity, 

 though essential concomitants of life, form its 

 essence. 



