METABOLIC ACTIVITY OF NERVOUS SYSTEM 



371 



TABLE 5 



Showing nitrogen content iri terms of the non-proteins, the amino acids, the urea 

 and the ammonia in the brain of sheep 



ing when we recall that in the white matter the relation between 

 the lipoids and non-lipoids is nearly 1:1 or in other words one- 

 half the weight- of the solids given by the white matter is repre- 

 sented by the lipoids. Donaldson and Hoke ('05) found that 

 in the cross surface of the medullated nerve the relation of the 

 area of the axis cylinder to the area of the sheath is practically 

 1:1 in all the vertebrates studied. Recently Greenman ('13) 

 found a similar relation in the fibers of the peroneal nerve of the 

 albino rat and reports more recently ('17) a somewhat higher 

 value for the lipoids. Thus my own chemical observations agree 

 with the histological findings of others very nicely. It appears 

 therefore certain that the nitrogen values in these two forms of 

 nerve tissue would agree if the lipoids free solids were alone 

 compared. This seems to show quite clearly that non-protein 

 nitrogen is quantitatively related to proteins or active cell sub- 

 stance. We shall later find further evidence to support this 

 hypothesis of a quantitative relation of non-protein nitrogen 

 to the active cell substance as revealed by an analysis of different 

 parts of the central nervous system. 



THE NON-PROTEIN NITROGEN IN DIFFERENT PARTS OF THE 

 CENTRAL NERVOUS SYSTEM 



When we divide the central nervous system into four parts, 

 cerebellum, cerebrum, stem and spinal cord, we are also dividing 

 it into parts in which the content of lipoids is graded in the order 

 named. The object of this determination was therefore to de- 

 termine the quantitative distribution of the nitrogenous extrac- 

 tives in these four different parts in order to see whether the 



