GENERAL FEATURES OF NERVOUS TISSUES. 



123 



FIG. 35. 



Scheme of the Nerves of a Segment of the Spinal Cord : Gr gray, W white matter of spinal 

 cord. A anterior, P posterior root G ganglion on the posterior root N whole nerve, N' spinal 

 nerve proper, ending in M skeletal or somatic muscle, S somatic sensory cell or surface, Xin 

 other ways. V visceral nerve (white raimis communicans) passing to a ganglion of the sympa- 

 thetic chain 2, and passing on as V to supply the more distant ganglion <r, then as V" to the peri- 

 pheral ganglion <r' and ending in m splanchnic muscle, s splanchnic sensory cell or surface, x 

 other possible splanchnic endings. From 2 is given off the revehent nerve r. v (gray ramus 

 communicans) which partly passes backward toward the spinal cord, and partly runs as v. m, in 

 connection with the spinal nerve, to supply vasomotor (constrictor) fibres to the muscles (TO') of 

 bloodvessels in certain parts, for example, in the limbs. Sy, the sympathetic chain uniting the 

 ganglia of the series 2. The terminations of the other nerves arising from 2, a, a' are not 

 shown. 



