VASCULARITY IN THE NERVOUS SYSTEM 431 



zation of the whole cerebrospinal axis. The arteries of the bulb 

 are divisible into median and radicular, corresponding to the 

 groups supplying the hemispheres, and the same holds true 

 regarding the spinal cord. He gives a detailed account of the 

 origin of the vessels supplying each region of the brain. 



Krause ('76) finds that the capillary network in the human 

 spinal cord, in addition to being much wider meshed in the white 

 matter than in the gray, is widest in the anterior funiculi, closest 

 (in the white matter) in the posterior funiculi, particularly in 

 the fasciculus gracilis. 



The excess of the capillary supply of the gray matter over 

 that of the white matter is noted by all succeeding authors who 

 refer to the capillaries at all (Rudanowsky, Adamkiewicz, Kadyi, 

 Hoche, Sterzi, Cajal, etc.). Rudanowsky ('76) describes the 

 capillary network in the gray matter as being so fine as to en- 

 circle a single cell in each mesh. Adamkiewicz ('81) disagrees 

 with him on this point, but finds evidence of a delicate secondary 

 net within the primary capillary meshes, which does surround 

 single cells as Rudanowsky describes. 



The vessels of the spinal cord have been subjected to a careful 

 study by a number of later writers, who have described in detail 

 their development, arrangement, and distribution (Ross, Adam- 

 kiewicz, Kadyi, Hoche, Sterzi, Hoskins, etc.). Adamkiewicz 

 finds the capillaries in the gray matter of the human cord to be 

 relatively large, the net being densest and the capillaries largest 

 in the cell groups. The net is poorer in the dorsal horns than 

 elsewhere in the gray matter, except where these horns are as 

 large as the ventral ones, in which case the net is alike in both. 



Kadyi ('89) observes that the density of the capillary net is 

 not the same in all parts of the gray matter of the spinal cord. 

 He speaks, moreover, of 'true capillaries' (echte Capillaren)— 

 those vessels which are interpolated between the final arterial 

 branches and the first venous tributaries — of which the extent 

 in the cord is rather small, and 'precapillaries' (Vorcapillaren) , 

 arterial and venous, — those vessels which divide into twigs of 

 a still lower order, but yet resemble the capillaries in their lumen 

 and in the structure of their walls. Hoche ('99) also makes 



