550 



THE SPINAL CORD. 



gray matter in the posterior horn is not specially concerned in any elabo- 

 ration or transformation of afferent impulses immediately upon their arrival 

 at the cord. Indeed, we have seen that while there is ample evidence to 

 connect the nerve-cells, and therefore presumably the gray matter in general 

 of the anterior horn with the efferent motor fibres of the anterior root, there 

 is no corresponding evidence as to any large immediate connection of the 

 afferent fibres of the posterior root with the nerve-cells, or indeed any other 

 part of the gray matter of the posterior horn. We may add that, as we 

 shall point out later on, so essential is the concurrence of appropriate affer- 

 ent impulses to the due carrying out of complex coordinate motor or effer- 

 ent impulses, that we can scarcely expect to find any increase in the nervous 

 mechanisms devoted to the purely motor function of carrying out motor 

 impulses without a corresponding increase in the nervous mechanisms 

 belonging to the afferent impulses, by means of which these motor impulses 



FIG. 127. 



C 2 



s.lr 



C.b 



