758 VII. LIPID DISTRIBUTION IN SPECIFIC TISSUES 



and the least in the phospholipids. Little or no change takes place in the 

 case of the unsaturated phospholipids ; however, the saturated phospholipids 

 (including sphingomyelin), together with cholesterol and the cerebrosides, 

 increase markedly. 



McConnell and Sinclair 304 recorded variations in the lipid content of 

 rats, as related to age. Thus, the values for brain lecithin plus cephalin 

 on the moist basis were as follows: newborn rats, 1.14%; rats three weeks 



Table 15 

 The Comparative Composition of Human Brain as Influenced by Age u 



Table 16 



The Composition of Brain from Children and from Adults 



as Influenced by Age (Expressed in per Cent of Dry Tissue)" 



Source of sample 



Fetus New- Child 1 Child 2 Old 



Category (7-8 mo.) born (13 mo.) (14 mo.) man 



No. of samples examined 21 13 111 



Fat plus cholesterol, % 6.8 4.4 8.0 5.6 13.4 



Glycerophosphatides 



Ether-soluble, % 16.4 15.5 22.9 19.1 25.0 



Ether-insoluble, % 0.5 0.3 1.9 1.1 0.0 



Sphingomyelin, % 0.9 



Cerebroside, % 0.02 0.05 1.5 2.7 6.4 



Lignocerylsphingosine, % 0.07 



Substance X, % 0.1 0.4 0.3 0.4 



• K. Schuwirth, Z. physiol. Chem., 263, 25-36 (1940). 



old, 2.32%; and rats three months of age, 3%. Monde and Bieth 305 

 likewise reported a regular increase in phospholipids and fatty acids in the 

 brain of rats during postnatal development. Cerebrosides were present as 



304 K. P. McConnell and R. G. Sinclair, J. Biol. Chem., 118, 131-136 (1937). 



305 P. Monde and R. Bieth, Bull. soc. chim. biol., 33, 973-981 (1951). 



