On the Vital Principle. aj^ 



cton of any bodily caufe j and the impreffion 

 is fometimes fo powerful as to put an entire 

 ■flop to the vital motions, and thus produce 

 death. Again, organic lefions of the heart 

 and lungs have been obferved to take place 

 from extremes of pafTion ; and particularly, in 

 Mefmer's operations of animal magnetifm, feve- 

 ral perfons fpit blood by the mere ftrength of 

 imagination*. All thefe fafts equally difprove 

 the exiftence of a feparate vital principle, and 

 prove the dependance of the nervous energy 

 upon the brain. 



3. It is acknowledged, that in maniacal cafes, 

 the principal part of the difeafe confifts in de- 

 praved perception j and this depravation implies 

 a change in the mediym of perception, that is, 

 in the brain and nervous fyftem. Now it is 

 well known that madnefs is frequently produced 

 by caufes purely mental, and in perfons appa- 

 rently in good health. And as the patient's 

 fenfibility to very powerful ftimuli is much 

 diminifhed in maniacal cafes, they afford ano- 

 ther proof of the fubordination of the nervous 

 energy. 



4. Writers of unqueftionable credit have 

 obferved, that, in paralytic cafes, motion is fre- 

 quently deftroyed, while fenfe remainsfi as 



• See the Report of the Commilfioners. 

 t Haller. Phyf. torn. IV. p, 390. 



the 



