STUDIES ON THE REGENERATION OF THE PERO- 

 NEAL NERVE OF THE ALBINO RAT: NUMBER AND 

 SECTIONAL AREAS OF FIBERS: AREA RELATION OF 

 AXIS TO SHEATH 



M. J. GREENMAN 



The Wistar Institute of Anatomy and Biology 



THREE FIGURES 



The work here presented is part of a program of considerable 

 magnitude, bearing upon the growth of the nervous system, 

 now being carried out under the direction of Professor Donald- 

 son. The experiments thus far made have already suggested 

 so many new problems that it seems best to publish some of 

 tKe results now in hand while further observations are being 

 made. 



The primary object of this study was to determine the number 

 and size of the medullated nerve fibers within a regenerated 

 peripheral nerve of the albino rat and compare the conditions 

 on the side of the operation with those found in the correspond- 

 ing unoperated nerve of the opposite side in the same animal. 



The following series of animals furnished the data for this 

 study : 



Series 1. Animals nos. 1 to 79 inclusive. 



This series was used in perfecting the technique of operation and 

 no further record of it will appear. 



Series 2. Comprised 92 animals in all. From 18 of these, sections 

 suitable for the purposes of the study were obtained. 



These 18 animals, of different known ages, were operated and after 

 the lapse of varying periods of time were killed. 



The weight at the time of operation and at the time of killing is 

 given in all cases except one. One specimen, no. 100, was excluded 

 because although a young animal it did not gain in weight after the 

 operation, and two specimens, nos. 93 and 116, were excluded because 

 they were the only representatives of their respective age groups. The 



479 



THE JOURNAL OF COMPARATIVE NEDROLOGY, VOL. 23, NO. 5 



