580 BRAIN AND NERVES. 



dissolves more easily in warm alcohol and also in warm ether. It may 

 be obtained as extremely fine needles. Encephalin is, PARCUS thinks, 

 a transformation product of cerebrin. In the perfectly pure state it 

 crystallizes in small lamellae. It swells in warm water into a pasty 

 mass. Like cerebrin and kerasin, it yields a reducing substance (prob- 

 ably galactose) on boiling with dilute acid. 



As the purity and the chemical individuality of the above-mentioned bodies 

 is questionable, it is perhaps sufficient in regard to their preparation to simply 

 call attention to the cited works of MULLER, GEOGHEGAN, KOSSEL and FREYTAG. 

 All these methods split with barium hydroxide and purify the cerebroside by 

 solution in hot alcohol and a precipitation by cooling. 



Whether the above-described cerebrosides are chemical individuals or 

 mixtures, i.e., impure substances, is still undecided. The purest cere- 

 broside thus far investigated is undoubtedly THIERFELDER'S cerebron, 

 and there is hardly any doubt that the above-mentioned cerebrosides 

 consist essentially of this body. 



Cerebron. This cerebrin, isolated by THIERFELDER and WORNER 

 and then especially studied by THIERFELDER, was first isolated by GAM- 

 GEE and called pseudocerebrin by him. THUDICHUM'S phrenosin is, 

 according to GiES, 1 identical with cerebron. Cerebron can be prepared 

 directly from the brain without saponification with baryta, by treatment 

 with alcohol containing benzene or chloroform at a temperature of 50, 

 and hence it is considered as existing preformed in the brain. According 

 to THIERFELDER cerebron has the formula C^HgsNOg; it melts at 212, 

 dissolves in warm alcohol, and separates out on cooling. From proper 

 solvents (acetone or methyl alcohol containing chloroform) it may be 

 separated as small needles or plates. If cerebron is suspended in 85- 

 per cent alcohol at a temperature of 50 C. it balls together in amorphous 

 masses, and from these needle- and leaf-shaped crystals gradually form. 

 It is dextrorotatory, and in about a 5-per cent solution in methyl alcohol 

 (containing 75 per cent chloroform) is (a) D =+7.6 (KITAGAWA and 

 THIERFELDER). According to THIERFELDER it yields as cleavage prod- 

 ucts, galactose, cerebronic acid (THUDICHTJM " neurostearic acid ") and 

 a mixture of two bases, which have not been closely studied, of which one 

 is crystalline, gives a beautiful crystalline compound with HC1 and 

 has the probable composition CigH 39 NO2. The relation of these bases 

 to THUDICHUM'S base sphingosin has not been explained. Cerebronic 

 acid is crystalline, melts at 99-100 C. and gives a crystalline methyl 

 ester melting at 65 C. 



Cerebron can best be prepared, according to THIERFELDER and 

 KITAGAWA, by decomposing the protagon in methyl alcohol containing 



1 Thierfelder and Worner, Zeitschr. f. physiol. Chem., 30; Thierfelder, ibid., 43, 

 44, 46, with Kitagawa, ibid., 49; Gamgee, Text-book of Physiol. Chem., London, 

 1880; Thudichum, 1. c.; Gies, Journ. of Biol. Chem., 1 and 2. 



