298 THE FATTY ACIDS OF BRAIN LIPOIDS, I., 



Part i. Fatty Acids obtained by direct saponification op 



THE WHOLE BRAIN. 



i. Total fatty acids in humaii brain. 

 ii. The nature of the fatty acids in the human brain. 



Of the methods which have been proposed for the estimation, 

 of the fatty acids in tissues, the one which is based on the 

 soundest principle seems first to have been proposed by Lieber- 

 mann.* This method has been adopted here with certain modi- 

 fications! in estimating the total fatty acids in the brain, and 

 also in obtaining larger quantity of the acids for examination. 

 The modifications are necessary for tissues which, like the brain, 

 contain much unsaponifiable matter. 



i. Total Fatty Acids in Human Brain. 



The fresh brain, freed as far as possible from superficial con- 

 nective tissue and blood, was pounded in a mortar, and passed 

 through a wire-sieve. The whole was then thoroughly mixed, 

 and samples immediately weighed into small flasks, fifty grms. in 

 each sample, and covered with 150 c.c. of alcohol. These samples 

 were used subsequently as required. For saponification, .samples 

 were taken with 25grms. KOH, and heated for six hours in reflux 

 condenser. The alcohol was partially removed, and the concen- 

 trated solution evaporated in a porcelain dish with the addition 

 of sand and sodium bicarbonate. The hard, dried residue was 

 finely powdered, and thoroughly extracted with anhydrous ether 

 till the extracting fluid, on evaporation, left no significant residue 

 of cholesterol. The cholesterol-free soap-powder was then decom- 

 posed by HCl, and the fatt}' acids extracted with ether, washed 

 free of mineral acid, and dried in current of anhydrous CO.^. 



♦Liebermann, Pfliig. Arch. 72, 360. 



t This method has also been modified by Kumagawa and Suto (Biochem- 

 ische Zeitsehrift, Bd. ix., s.212), but the slight modifications which they 

 have suggested do not entitle them to the claim to be authors of the method. 

 Many subsequent authors also seem to be unaware that Liebermann was 

 the author of this method. 



