ANIMAL AND VEGETABLE 181 



muscles and nerves will be normal, as they are still in 

 connection with the nerve cells of the spinal cord which 

 control their nutrition." 



True. But where does the impulse originate, nor- 

 mally ? In a nerve cell or cells in the motor area of the 

 brain. If that cell or those cells fail to act, no impulse can 

 pass from brain to muscle. In other words, the rest of 

 the apparatus is in working order, but some of the battery 

 cells have given out. 



" But if the paralysis is due to disease either of the 

 spinal cord or of the nerves, this nutritive influence can no 

 longer be exercised over the nerves or muscles." 



Of course not. There is a partial or total loss of 

 conductivity by reason of the influence of disease upon the 

 spinal cord or the nerves. The motor apparatus generally 

 may be in working condition, but no energy can be con- 

 veyed to it, and it cannot, therefore, be set in motion. 



