256 NERVOUS SYSTEM. LiECT. XIV. XV. 



provoke pain. The anterior and posterior spinal nerves, 

 and some other nervous branches, possess a single function 

 only. 



Flourens Longet, and other physiologists, have also dis- 

 tinguished in the nervous centres, some parts which preside 

 over sensations only, and others, again, exclusively de- 

 voted to movements. 



A nervous fasciculus is made up of a great number of 

 filaments, every one of which is separately able to transmit 

 the influence of the will, or of some stimulant, without the 

 other filaments with which it is in contact, participating in 

 the action. 



Ganglionic System. Besides the cerebro-spinal, there 

 exists a second nervous system, which, notwithstanding its 

 numerous connexion with the first, does not, when irritated, 

 excite either movements or sensations. It is the ganglionic 

 nervous system, composed of ramifications, chiefly dis- 

 tributed to the apparatus of organic life. These ramifica- 

 tions gradually unite, interlace with each other, and have 

 in their interstices a globular matter, which seems also to 

 exist in the central masses. 



In this system, irritations, manifested by certain peculiar 

 movements, excited chiefly in the intestines, are slowly 

 propagated, and continue to be so, even when the irritating 

 action has been removed. A muscle, which has been 

 deprived for a certain time of all communication with the 

 centres or ganglia, of this system, loses the property of 

 contracting under the influence of irritation of its cerebro- 

 spinal nerves. 



These few words concerning the nervous action will, I 

 hope, be sufficient to make you understand the importance 

 of the results to which we are come on the physiological 

 action of the electric current. 



Peculiarities of Electric Irritation of the Nerves. I con- 



