FUNCTIONS OF THE SPINAL COED. 



497 



that, rather, as there are separate nerve-fibres for motor 

 and for sensitive impressions, so in the cord, separate and 

 determinate parts serve to conduct always the same kind 

 of impression. 



The important and philosophical labours of Dr. Brown- 



* The above diagram (after Brown-Sequard) represents the decus- 

 sation of the conductors for voluntary movements, and those for 

 sensation : a r, anterior roots and their continuations in the spinal 

 cord, and decussation at the lower part of the medulla oblongata, m ; 

 p r, the posterior roots and their continuation and decussation in the 

 spinal cord ; g g, the ganglions of the roots. The arrows indicate the 

 direction of the nervous action ; r, the right side ; I, the left side. 

 I, 2, 3, indicate places of alteration in a lateral half of the spino- 

 cerebral axis, to show the influence on the two kinds of conductors, 

 resulting from section of the cord at any one of these three places. 



