ARCHITECTURE AT MATURITY. 189 



The quantitative relations of grey and white matter 

 composing the human cord are illustrated by the follow- 

 ing diagram. The curves are intended to illustrate in 

 terms of square millimeters the area of the cross-section 

 of the cord at the level of each spinal nerve. In this 

 figure the white substance and the grey are contrasted 

 with one another as well as the united sectional areas of 

 the spinal nerves. The curves show that, corresponding 

 to the lumbar and cervical enlargements, a great increase 



FIG. 32. Diagram showing by curves the area of several portions 

 of the cord. Areas indicated in square millimeters on the 

 vertical axis. The level of the spinal root is marked on the 

 horizontal axis, the first cervical being that recorded at 

 the extreme right. A, the area of the total white matter at 

 the different levels ; 13, the united area of the spinal nerve 

 roots beginning at the sacral end of the cord ; C, the area of 

 the grey matter at the different levels. (Compiled from 

 measurements by Stilling.) 



in the area of the grey substance occurs, while the 

 white substance, taken as a whole, increases in area 

 'from the caudal to the cephalic end, with a special 

 expansion in the cervical region. The united sectional 

 area of the nerves show an almost steady increase, 

 which is slightly accentuated at the points where the 

 nerves for the limbs join the cord. 



In these curves no attempt has been made to repre- 



