7l6 youmal of Comparative Neurology and Psychology. 



In the course of the present investigation it was found possible to 

 corroborate the previous finding by a study of the conditions in the 

 unoperated leg of frog E, and to determine the condition existing 

 among the afferent nerve fibers in the left or operated leg of frog E. 

 Table XVII gives the measurements from frog E for the afferent 

 fibers, and for the combined afferent and efferent fibers, and for the 

 combined nerve fibers from frog IIB. Because of the absence of 

 efferent nerve fibers from the operated leg of frog E the total number 

 of nerve fibers is decreased at each level. To make possible com- 

 parison with the unoperated leg and with frog IIB both the full 

 number and the relative number were included, the latter in each 

 instance standing alone below the former. 



The findings for frog IIB are confirmed by the measurements for 

 the unoperated leg of frog E. The average area of the 22 largest 

 nerve fibers at the level above the branches to the thigh is 257 square 

 micra. That of the corresponding 16 nerve fibers at the level below 

 the branches is 194 square micra, while the corresponding 8 nerve 

 fibers in the branches have an average area of 276 square micra. 

 Similarly the largest nerve fibers at the entrance to the shank are 

 found in the branches to the shank and not in the main trunks below 

 the branches. 



In the operated leg there is shouTii a similar distribution of the 

 largest afferent nerve fibers at each level to the tissues of the adjacent 

 segment. Table XVII shows that larger medullated nerve fibers, 

 both muscular and cutaneous, are found in the thigh than in the 

 shank. 



Relation of the Akea of the Axis Cylindek to the Area of 

 THE Meduelaey Sheath IN" Ceoss Sections of the Largest 

 Medullated Nerve Eibers in the Operated Leg of Frog E. 



A swollen condition of the individual nerve fibers in the operated 

 leg is shown by the uniformly larger size of the nerve fibers on this 

 side when compared with corresponding nen^e fibers on the unoper- 

 ated side. As this condition prevails throughout the leg it does not 

 vitiate the results of a comparison of the caliber of the nerve fibers 

 at various levels of the operated leg. It does unfortunately prevent 



