104 



ANATOMY 



The data are arranged in age groups and are for Albinos of 

 normal size for their ages. In some cases the body weight at 

 killing was below normal, owing to lung infection. 



The data show approximately the same number of fibers on 

 each side. No sex difference was found. There is an indica- 

 tion of a loss of fibers after 251 days. This was possibly due 

 to lung infection. 



TABLE 65 



Number of myelinated fibers in the 'peroneal nerve of the albino rat — sections from 



the middle level; based on Greenman' s table 8, '17 



TABLE 66 

 Normal albinos: Sectional area of ten largest fibers in ^x-; relation of axis to sheath 



In an earlier study on cross sections of the largest fibers 

 Greenman ('13) found the percentage value of the area of the 

 axis in osmic acid preparations to be 49.9 per cent, as given in 

 table 66. 



These areas were computed from the mean diameters of the 

 entire fiber and of the axis. In this later study (Greenman, 

 '17) the areas of axis and of entire fiber were obtained plani- 



