Ingbert, Ventral Roots of spinal Nen'cs. 235 



fine fibers in the ventral to those in the dorsal roots is 

 1:4-7 (page 231). 



13. There are about 122.953 (60.90%) large fibers (7. 5 « 

 or more in diameter) in the ventral roots, and 372,45 i 

 (40%), in the dorsal roots — a ratio of 1:2.2 (page 231). 



14. In the ventral roots the fibers, the diameter of which is 

 less than 7.5 ;l, are most abundant in the thoracic re- 

 gions. 



Fibers less j" C. VI =r \2i:L 

 than 7.5 // \ Th.VI = ^ocj^ 

 in diameter ( S. I. = 14^, 



(D) NUMBER UF FIBERS PER SO. MM. OF THE CROSS-SECTION. 



15. There are on the average 7,687 medullated nerve fibers 

 to every sq. mm. of the cross-sections of the ventral 

 roots of man against i 1,900 for the dorsal roots (page 

 231). 



16. In C. VII- VIII the dorsal roots have nearly twice as 

 many (9,800) nerve fibers per sq. mm. of the cross-sec- 

 tion as the ventral (5,500), and in S. I. the dorsal root 

 has more than three times as many (13,800) as the ven- 

 tral (4,300) (page 216). 



i"] . In the thoracic region the number of nerve fibers per 

 sq. mm. of the cross-section of the roots is nearly the 

 same for both ventral and dorsal roots — namely, about 

 12,000 (page 216). 



18. Stilling's estimate for the fibers per sq. mm. in the 

 ventral and dorsal roots is close to the estimation here 

 made, for fibers the diameter of which is 7. 5 11 or more. 

 Fibers below 7.5 // Stilling did not recognize and did 

 not include. 



No. of fibers 7.5 // or more in diameter, per sq. mm. in the ventral roots : 



Stilling 4,231 

 Author 4>556 



No. of fibers above 7.5// or more in diameter, per sq. mm. in the dorsal roots: 



Stilling 4,537 

 Author 4,960 



