80 PHYSIOLOGY. 



as what I said in XCVIL, that both the inherent and nervous 

 power have a constant dependence upon the animal power. 

 The proofs I have chiefly reserved for this place, where the 

 proposition is of more importance ; indeed it is a very leading 

 one in the whole of our Pathology, and therefore I take so 

 much pains in order to support it in differing from (I do not 

 like the expression of confuting) Dr. Haller. I think proper 

 now to illustrate this further, and to shew that the inherent 

 power is in a constant dependence upon the nervous, or more 

 properly upon the animal power. 



" I shall give instances with respect to both the voluntary and 

 involuntary motions : I begin with the involuntary, because in 

 these especially it has been attempted to show the independence. 

 It is alleged that the action is produced merely by the mechani- 

 cal power of the stimulus acting upon the inherent power, 

 independently of any action or energy of the brain or nerves ; 

 but, from considering the effects of the passions of the mind 

 upon the state of action of the heart, I say that the passions 

 which diminish the tone or action of the heart, are proofs 

 that the energy of the brain is constantly necessary. Fear is 

 allowed to weaken the action of the heart, as much as anger can 

 increase it ; and nobody alleges that the heart is exempt from 

 the causes of fear. There is no doubt that it is one of the 

 pathemata reprimentia or sedantia, and that it and every 

 motion of the mind acts in the brain only, and acts by with- 

 holding that power which is otherwise constantly necessary ; and 

 when these operate so immediately upon the heart, it is a proof 

 that the action of the heart depends upon some energy derived 

 constantly from the brain. But we have another proof from the 

 action of the heart being destroyed by a ligature upon the nerves. 

 This fact is disputed by Haller; but he has mentioned all the ex- 

 periments which shew that by putting ligatures upon the eighth 

 pair, or par vagum, and by cutting through the intercostals, a ces- 

 sation of the heart's action, and death itself, in a shorter or longer 

 time, is constantly induced in some of these experiments, very 

 suddenly, and in others at no great interval ; and in all of them 

 the effect at last is that the action of the heart is entirely de- 

 stroyed. With regard to these experiments, which shew that 

 the destruction of the action of the heart succeeds slower in 



