OF CHEMICAL FORCES. 5 



is in no way dependant on the presence of this 

 apparatus ; that the process of nutrition proceeds 

 in those parts of the body where the nerves of 

 sensation and voluntary motion are paralysed, ex- 

 actly in the same way as in other parts where 

 these nerves are in the normal condition ; and, on 

 the other hand, that the most energetic volition is 

 incapable of exerting any influence on the contrac- 

 tions of the heart, on the motion of the intestines, 

 or on the processes of secretion. 



The higher phenomena of mental existence can- 

 not, in the present state of science, be referred 

 to their proximate, and still less to their ultimate 

 causes. We only know of them, that they exist ; 

 we ascribe them to an immaterial agency, and that, 

 in so far as its manifestations are connected with 

 matter, an agency entirely distinct from the vital 

 force, with which it has nothing in common. 



It cannot be denied that this peculiar force ex- 

 ercises a certain influence on the activity of vege- 

 tative life, just as other immaterial agents, such 

 as Light, Heat, Electricity, and Magnetism do ; but 

 this influence is not of a determinative kind, and 

 manifests itself only as an acceleration, a retarding, 

 or a disturbance of the process of vegetative life. 

 In a manner exactly analogous, the vegetative life 

 reacts on the conscious mental existence. 



There are thus two forces which are found in 

 activity together ; but consciousness and intellect 

 may be absent in animals as they are in living 



