1905.J 



Cord of the Macaque Monkey. 



139 



and the white substances and of their component parts, between the region of 

 one spinal nerve and that of the next, is shown in the following chart (XX). 

 The calculations were made with the mean sectional area figures as given in 

 Tables I to V, and XII, XIII. 



Taking the total area of the cross-sections of the cord as the example 

 (Chart XX, heavy black line, S), the method employed was as follows : The 

 mean sectional area of the first lumbar region was taken as unity. The value 

 of the second point of the curve was obtained by dividing the mean sectional 

 area of the second lumbar regio by that of the first lumbar ; similarly 

 the value of the third point of the curve was obtained by dividing the mean 

 sectional area of the third lumbar region by the mean sectional area of the 

 second lumbar, and so on throughout the remaining regions of the cord. 



To render comparison easy, the curves are arranged in three separate 

 groups in the same chart. The rate of increase and decrease in the section 

 area of the cord, the grey and the white substance is indicated by the curves 

 in Group S, that of the white substance and its component parts, the ventro- 

 lateral and the dorsal columns, in Group Z, and that of the grey substance 

 and the ventral and dorsal horns in Group B. 



All the curves are comparable one with another. 



Table XXI. — Kate of Increase and Decrease in the Sectional Area of the 

 Cord and of each of its Component Parts. The mean sectional area 

 of the first lumbar region is in each case taken as unity (Chart XX). 



Eegion of 

 cord. 



Cross- 

 section of 

 tlie cord. 



G-rey 

 substance. 



'Dorsal 

 horns. 



Ventral 

 horns. 



White 

 substance. 



Dorsal 

 columns. 



Ventro- 

 lateral 

 columns. 



Lumbar — 

















I 



1-0 



1-0 



1 -o 



1 -o 



1-0 



1 -o 



1 -o 



II 



1 -1 



1 -4 



1-3 



1 -4 



1 -1 



1 -1 



1 -o 



III 



1 -1 



1 -2 



1 -o 



1 -4 



1 -o 



I -o 



1 



IV , 



1 -3 



1 -6 



1 -2 



1-7 



1 -2 



1 -1 



1 "2 



V .. 



0-9 



1 -I 



1 -1 



1 -1 



0-9 



0-8 



0-9 



VI 



0-8 



0-8 



1 -o 



0-8 



0-7 



0-7 



0-7 



VII 



0-7 



0-8 



1 -o 



0-7 



0-7 



0-7 



0-7 



Sacral — 

















I 



0-7 



0-7 



0-8 



0-7 



0-7 



0-6 



0-7 



II 



0-8 



0-8 



0-8 



0-8 



0-7 



0-8 



0-7 



III 



0-7 



0-8 



0-8 



0-7 



0-7 



0-8 



0-7 



IV ... 



0-8 



0-8 



0-9 



0-8 



0-7 



0-8 



0-7 



Coccygeal — ■ 

















,{ 



0-7 



0-8 



0-8 



0-7 



0-7 



0-6 



0-7 





0-5 



0-5 



0-6 



0-5 



0-6 



0-5 



6 



Ill 



0-5 



0-5 



0-5 



'4 



0-5 



0-4 



0-6 



Thus the total area of the cord in the second lumbar is 1*1 times its area 

 in the first, from thence to the third lumbar the increase is at the same rate 



