LIPIDS PRESENT IN BRAIN AND NERVOUS TISSUE 755 



tration of all phospholipid fractions was lower in the supernatant fluid 

 than in any of the particle fractions. Sphingomyelin and cephalin were 

 localized mainly in the mitochondria, whereas the concentration of lecithin 

 was highest in the microsomes. 



(3) Physiologic Factors Altering the Composition 

 of Normal Brain 



a. The Effect of Species on Brain Lipids. Lanfranchi 294 reported that 

 the proportion of cerebroside in the brain increases with phylogenetic evolu- 

 tion. Cerebrosides were shown to be absent from the brain of the octopus 

 (Octopus vulgaris); in the teleost scorpion-fish, or toad-fish (Scorpaena 

 porcus), they averaged 3.37% of the dry weight, while a mean value of 

 3.69% was noted in cartilaginous fishes, for instance the small-spotted 

 dogfish (Scyllium canicula). The following figures (based on dry weight) 

 for cerebroside were noted in the terrestrial animals: common toad (Bufo 

 vulgaris), 3.10%; Greek tortoise (Testudo graeca), 6.9%; fowl (Gallus 

 domesticus) , 6.02% and, representing the mammals, the black rat (Mas 

 rattus), 10.23%. Study of the chicken embryo showed that the cerebro- 

 side content increased with ontogenetic development also; at ten days the 

 value was 0.12% (moist weight), at twenty days, 1.37%. Patterson and 

 associates 295 were unable to demonstrate the presence of cerebrosides in 

 the head portion of the honey bee. 



Argiris 296 reported, in 1908, that cerebrosides were present in only ex- 

 tremely small amounts in the brain tissue of codfish (Gadus morrhua) and 

 haddock (Gadus aeglefinus) ; however, as early as 1893, Kossel and Frey- 

 tag 297 had isolated cerebrosides from the brain of the sturgeon (Acipenser 

 sturio). The presence of cerebrosides in the brain of chickens and ducks 

 has also been reported. 296 



The concentration of various lipids in the brain of a number of mammals 

 has been investigated by Johnson, McNabb and Rossiter. 298 These data are 

 summarized in Tables 13 and 14, on page 756. 



Practically no esterified cholesterol occurs in any of the several species 

 reported in Tables 13 and 14. Moreover, Ellis and Gardner, 184 in their 

 classical studies on cholesterol, could find no trace of esterified cholesterol 



294 F. Lanfranchi, Arch. set. biol. (Italy), 24, 120-124 (1938). 



295 E. K. Patterson, M. E. Durnm, and A. G. Richards, Jr., Arch. Biochem., 7, 201- 

 210 (1945). 



296 A. Argiris, Z. physiol. Chem., 57, 288-295 (1908). 



297 A. Kossel and F. Freytag, Z. physiol. Chem., 17, 431-456 (1893). 



298 A. C. Johnson, A. R. McNabb, and R. J. Rossiter, Biochem. J., 48, 573-577 (1948). 



