610 BRAIN AND NERVES. 



baryta-water. Following a method essentially the same, but differing 

 slightly, GEOGHEGAN prepared, from the brain, a cerebrin with the 

 same properties as MULLER' s, but containing less nitrogen. Accord- 

 ing to PARCUS l the cerebrin isolated by GEOGHEGAN, as well as by 

 MULLER, consists of a mixture of three bodies, " cerebrin," " homo- 

 cerebrin," and " encephalin." KOSSEL and FREYTAG isolated two 

 cerebrosides from protagon which were identical with the cerebrin and 

 homocerebrin of PARCUS. According to these investigators, the two 

 bodies phrenosin and kerasin, as described by THUDICHUM, seem to be 

 identical with cerebrin and homocerebrin. 



Cerebrin, according to PARCUS, has the following composition: C 

 69.08, H 11.47, N 2.13, 17.32 per cent, which corresponds with the 

 analyses made by KOSSEL and FREYTAG. No formula has been given to 

 this body. In the dry state it forms a pure white, odorless, and tasteless 

 powder. On heating it melts, decomposes gradually, smells like burned 

 fat, and burns with a luminous flame. Melting-point is 170-176 C. It 

 is insoluble in water, dilute alkalies, or baryta-water; also in cold alcohol 

 and in cold or hot ether. On the contrary, it is soluble in boiling alcohol 

 and separates as a flaky precipitate on cooling, and this is found to con- 

 sist of a mass of globules or grains on microscopical examination. Cere- 

 brin forms a compound with baryta, which is insoluble in water and is 

 decomposed by the action of carbon dioxide. The variety of sugar 

 split off on boiling with mineral acids the so-called brain-sugar is, 

 as THIERFELDER 2 first showed, galactose. On cleavage with nitric acid 

 fatty acids (stearic acid) were obtained. 



Kerasin (THUDICHUM), or homocerebrin (PARCUS), has the following 

 composition: C 70.06, H 11.60, N 2.23, and 16.11 per cent. Enceph- 

 alin has the composition C 68.40, H 11.60, N 3.09, and 16.91 per cent. 

 Both bodies remain in the mother-liquor after the impure cerebrin has 

 precipitated from the warm alcohol. These bodies have the tendency 

 of separating as gelatinous masses. Kerasin is similar to cerebrin, but 

 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. 



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. 



1 Geoghegan, Zeitschr. f. physiol. Chem., 3; Parcus, Ueber einige neue Gehrinstoffe, 

 Inaug.-Diss. Leipzig, 1881. 



2 Zeitschr. f. physiol. Chem., 14. 



