268 DR. PHILIP'S OBSERVATIONS OW" "^HT 



sudden impression made on the nervous system, by which the whole of the 

 functions are instantaneously destroyed,) the sensorial functions are the first 

 which cease, all the other powers of the system remaining more or less perfect, 

 and any imperfection which appears in them not directly depending on the 

 loss of the sensorial power. 



Of the sensorial functions, sensation and volition are the only ones which 

 we are called upon to consider here, because they alone have any share in 

 maintaining animal life. That these functions are essential to the maintenance 

 of life in all the more perfect animals, will, I think, appear from what I am 

 about to lay before the Society. 



The following may be regarded as the nervous functions properly so called. 

 The excitement of the muscles of voluntary motion, by which through the in- 

 tervention of the nervous system, they in their usual functions are subjected to 

 the sensorial power ; the occasional excitement of the muscles of involuntary 

 motion, by which under certain circumstances the sensorial power is also 

 capable of impressing them through the nerves, particularly when under the 

 influence of the passions ; the act of causing an evolution of caloric from the 

 blood, by which the due temperature of the animal body is maintained ; the 

 act of forming from the blood the various secreted fluids, and of maintaining 

 the other assimilating processes by which the healthy structure of every part 

 of the body is preserved. 



The first of these functions is universally acknowledged to be a function of 

 the nervous power, properly so called ; but there has been much difference of 

 opinion respecting the way in which it operates. The older physiologists be- 

 lieved that the muscles derive their power from the nervous system. Haller* 

 was the first who taught that the muscular power belongs to the muscle itself, 

 to which the nervous power bears no relation but that of a stimulus, and 

 endeavoured to support those opinions by experiment. His opponents, however, 

 objected to his inferences, because, although the division of the nerves may 

 prevent the muscle from receiving more nervous power, it does not deprive it 

 of that already bestowed upon it, either existing in the muscular fibres them- 

 selves, or dispersed through them in nerves too small to be removed ; and this 

 objection appeared to be strengthened by the muscles of involuntary motion, 



* Element. Physiolog. 



