Dunn, Medullated Nerve Fibers. 



707 



mass of the tissue iunervated, that is to the area of the skin and to 

 the weight of the muscles. This is with reference to the number of 

 nerve fibers in the primary branches, without correction for splitting 

 fibers. 



Estimation of the JSTumber of Efferent Medullated Nerve 

 Fibers in the Leg of Erog E, and their Distribution to 

 THE Segments of the Leg. 

 Our numerical findings would be complete if we could add to them 

 an estimation of the number of efferent medullated nerve fibers at 

 the various levels. This estimation would be made by finding the 

 differences at the various levels between the combined fibers on the 

 unoperated side and the afferent fibers on the operated side. In 

 making and discussing such an estimation the question of the drop- 

 ping out of efferent nerve fibers from the unoperated leg is of prime 

 importance. 



TABLE XIII. 

 Estimating the number of efferent medullated nerve fibers in the leg of frog E. 



At entrance to the thigh .... 

 Below branches to the thigh . 



Estimated to thigh 



At entrance to the shank . . . . 

 Below branches to the shank 



Estimated to shank 



Afferent. 



L. 

 4483 

 2424 



2059 



2531 

 1535 



996 



Total. 



R. 

 6398 

 3452 



2946 



3415 

 1998 



1417 



Efferent. 



Difference. 

 1915 



1028 



887 



884 

 463 



421 



Table XIII contains the estimation of the efferent fibers at the 

 various levels of the main trunks, and Tables XIV and XV contain 

 the estimations for the branches to the thigh and the shank respec- 

 tively. 



According to Table XIII the estimated number of efferent medul- 

 lated nerve fibers to the thigh is 887 nerve fibers. In Table XIV 

 the number for the primary branches is 823. The difference between 

 these, 64 fibers, shows a loss of fibers from the thigh. In all our 



