450 



C. G. MACARTHUR AND E. A. DOISY 



Wtinqms. 



80 



72 



64 



56 



48 



+0 



32 



i+ 



16 



J6 



24- 32 



1/ me In months 

 Fig. 1 



40 



48 



56 



compounds in the same way as the extractives, certain lipins, and 

 nucleoproteins. This is true whether one considers the sheath 

 as nutritional or insulating in function. In comparing nerve 

 activity with other tissues, it would probably be more exact, 

 therefore, to use data on the axis cylinders and not the whole 

 nerve (Donaldson, '16). 



