298 ANATOMY AND PHYSIOLOGY 



These may all be exercised independently of the brain, by cells 

 in the posterior and anterior horns with their sensor and motor 

 nerve connections. v (Other functions will be mentioned in connec- 

 tion with those of the brain.) 



The function of the spinal nerves is to connect all parts of the 

 body (except face, chin and anterior part of head) with the spinal 

 cord, for the purpose of conducting sensor and motor impulses to 

 and from the cord. 



NERVE STIMULUS 



In referring to motor nerves we have thus far mentioned their 

 natural stimulus only, that is the impulse generated by a sensor 

 or motor cell. The electric current applied to a motor nerve in any 

 part of its course will excite its activity, showing in muscle contrac- 

 tion, etc. This is an artificial stimulus, and the most powerful 

 one known. 



