Chap, xvi.] THE SPINAL CORD. 141 



the grey matter (Fig. 87). The ganglion cells of the 

 anterior horn and the cells of Clarke's column have, 

 in addition to these branched processes, generally one 

 unbranched pale process (occasionally, but rarely, this 

 is double), which takes its origin in the cell substance 

 with a thin neck. This is the axis cylinder process of 

 Deiters ; it becomes invested sooner or later in a 

 medullary sheath, and then represents a medullated 

 nerve-fibre, as mentioned on a former page. The 

 ganglion cells of the posterior horns have no axis 

 cylinder process, all processes being branched and 

 connected with the ground nerve network in the same 

 way as the branched processes of the ganglion cells of 

 the anterior horns. 



Anastomoses between the processes of the ganglion 

 cells of the anterior horns have been observed in a 

 few instances (Carriere). 



182. The ganglion cells of the anterior horns and 

 those forming Clarke's column i.e., the ganglion 

 cells with axis cylinder process are considered as 

 motor, the others as sensory ganglion cells ; that is to 

 say, the former are connected with a motor nerve-fibre, 

 the latter with a sensory fibre ; but it would be quite 

 incorrect to say that all motor fibres are connected 

 with the former, all sensory fibres with the latter. 



183. The white and grey matter is supplied with a 

 large number of blood-vessels, the capillaries being 

 more abundant and forming a more uniform network 

 in the grey than in the white matter ; in the latter, 

 most of them have a course parallel with the long 

 axis. The blood-vessels are ensheathed in lymph 

 spaces (perivascular spaces of His), and the ganglion 

 cells are each surrounded by a lymph space (peri- 

 cellular space). 



