BODY TISSUES AND FLUIDS 



469 



THE RELATIVE PROPORTIONS OF THE CONSTITUENTS OF THE BRAIN OF THE ALBINO RAT 



AT DIFFERENT AGES 



CONSTITUENTS IN PER CENT OF TOTAL SOLIDS 



DISTRIBUTION OF SULPHUR IN PER CENT OF TOTAL S 



DISTRIBUTION OF PHOSPHORUS IN TERMS OF TOTAL P 



Protein P 



Lipoid P 



Water Soluble P. 



13.3 

 33.2 

 53.5 



13.45 

 34.95 

 51.6 



5.9 



52.85 

 41.25 



8.7 

 57.3 

 34.0 



7.3 

 64.1 

 28.6 



6.8 

 67.6 

 25.6 



contain one molecule of oleic and one of palmitic acid as the fatty acids. 

 The formula would thus be written : 



H 2 C O COC 17 H 33 



I 

 H C O COC 15 H 31 



H 2 C O P = O 



H(T^ O CH 2 .CH 2 



\ 

 (OH.) t -N 



HO 



Cephalin differs from lecithin chiefly in containing as its basic sub- 

 stance amino-ethyl alcohol instead of cholin. Levene and Rolf have shown 



