BRAIN AND NERVES. 391 



utmost perfection in man. On the system of nerves 

 depends sensation, and there can be no doubt that the 

 more exalted the order of intelligence displayed, the 

 more exquisitely delicate is the nervous system. Thus, 

 in this world, refined genius must necessarily be at- 

 tended with <& condition of sensibility which, too fre- 

 quently, to the possessor is a state of real disease. 



It must be evident to every reader that but very few 

 of the striking features of animal life have been men- 

 tioned in the rapid survey which has been taken of the 

 progress of animal organization. The subject is so 

 extensive that it would be quite impossible to embrace 

 it within any reasonable limits; and it furnishes 

 matter so curious and so instructive, that, having once 

 entered on it, it would have been difficult to have made 

 any selection, and we must have devoted a volume to 

 the aesthetics of natural science. Passing it by, there- 

 fore, with the mere outline which has been given, we 

 must proceed to consider some of the conditions of 

 vitality. 



Bell has proved that one set of nerves is employed in 

 conveying sensation to the brain, and another set in 

 transferring the desires of the will to the muscles. By 

 the separation of a main branch of one of the nerves 

 of sensation, although all the operations of life will still 

 proceed, the organ to which that nerve goes is dead to 

 its particular sense. In like manner, if one of the 

 nerves of volition is divided, the member will not obey 

 the inclination of the brain. It is evident, therefore, 

 although many of the great phenomena of vital force 

 are dependent on the nervous system, and the paralysis 

 of a member ensues upon the separation or the disease 

 of a nerve, that the nerves are but the channels through 

 which certain influences are carried. The vis vit& or 

 vital principle for we are compelled by the imperfection 

 of our knowledge to associate under this one term the 

 ultimate causes of many of the phenomena of life is a 



