710 'Journal of Comparative Neurology and Psychology. 



A similar comparison may be made from the same tables showing 

 the relations in the shank of the right leg of frog E. Here also 

 between the level above the branches to the shank and the level below 

 the branches to the shank, a number of nerve fibers have dropped out. 

 The same arguments for the efferent character of these nerve fibers 

 hold as were used for those of the thigh. 



The existence then of a loss from among the efferent meduUated 

 nerve fibers in the unoperated leg of frog E vitiates to a certain 

 extent the estimations for the efferent nerve fibers in frog E. The 

 findings, however, for a large number of muscular branches in the 

 thigh and the shank, as shown in Tables XIV and XV, run so evenly 

 for the various branches, and the probable number of fibers which 

 has dropped out from each branch is so small, that we feel justified 

 in discussing the results as they stand without correction. 



Sherrington, 1894, after investigations of single muscle branches 

 in the cat and monkey, found that "In a muscular nerve trunk from 

 one-third to one-half of the myelinate fibers are from cells of the 

 spinal root ganglion." The fibers passing by a muscular nerve trunk 

 include, according to Sherrington, fibers passing to adjacent tissues, 

 such as the tendons and the perimysium. I have not myself been 

 satisfied that there may not be some innervation of tissues lying not 

 immediately adjacent to the muscles from the afferent medullated 

 nerve fibers running in the so-called muscle branches. It seems 

 possible that there may be still to be described a considerable nerve 

 supply to subcutaneous tissues not passing by way of the cutaneous 

 branches and it is hoped that this may be shown later. The findings 

 of Head and Rivers, 1908, demand for their anatomical interpreta- 

 tion such a layer of nerve endings lying between the deep muscular 

 endings and the superficial cutaneous endings. And such a distribu- 

 tion of the afferent nerve fibers would account for the rather large 

 number of afferent pathways in trunks to the muscles which Sher- 

 rington found in the cat and the monkey, and which has been found 

 here for the frog. 



Without attempting to correct for lost fibers, the findings show the 

 number of estimated efferent medullated nerve fibers in the primary 

 muscular branches. Tables XIV and XV, to be approximately equal 



