THE NERVOUS SYSTEM. 447 



which it pervades ; but it cannot give them to this, and far 

 less can I believe that it gives to this properties which it 

 itself does not possess : and, as to its performing the offices 

 of the part which it pervades, the thought is not entertained ; 

 and yet, except by admitting such an absurdity, I cannot see 

 how the power of secretion, nutrition, &c. can be ascribed to 

 nerves. The hypothesis is usually confined to the ganglionic 

 system : and the encephalon, spinal chord, and encephalo-spinal 

 nerves are considered to be appropriated to the intellectual and 

 moral functions, sensation, volition, and the mutual influence of the 

 brain and rest of the body. That the ganglia and ganglionic 

 nerves are developed in proportion to the activity and force of 

 the circulation, and to the development and activity of the functions 

 of organs, is no more an argument for the dependence of the vital 

 properties of these upon them, than the simultaneous development 

 of the ganglia and of the various viscera in early life. The sooner 

 the viscera are formed, the sooner must the ganglia and nerves 

 which convey influence to and from each of them be also formed ; 

 and, the more bulky and active an organ, the more nerves will it 

 require to influence* and be influenced by other organs. All 

 must allow that the ganglia and ganglionic nerves cannot be for 

 the purpose of vitality alone, since branches from both anterior 

 and posterior encephalo-spinal nerves join them and form part of 

 them. 



I should consider the functions of all nerves to be analogous 

 to each other. The spinal chord and encephalo-spinal nerves do 

 not give properties ; they communicate only between the brain and 

 the rest of the body. They convey to the brain an impression of the 

 state in the form of sensation ; and they convey an influence from 

 the brain in the way of emotion or volition. They do not bestow 

 the qualities of the brain, much less convey qualities which it has 

 not. They convey volition, and the influences of the moral feel- 

 ings, from the brain, and carry back the impressions of sensation 

 to the brain. Analogy would incline us to suppose that nerves 

 running between other parts would convey to those parts, in either 

 direction, the impressions of the state of the communicating parts, 

 this impression, like the impressions of sensation when followed 

 by volition, being sometimes followed by an influence to some 

 third organ or some other portion of the first organ. 



Dr. Brachet concludes from his experiments that the encephalic 

 nerve, called pneumono-gastric, gives moving power to the air- 



H H 



