CEREBRIX, KERASIN, ENCEPHALIN. 579 



acids. The cerebrosides isolated from the brain are cerebrin, kerasin r 

 encephalin, and cerebron, but it must be remarked that there is ro doubt 

 that sometimes the same body of varying purity has received different 

 names. The bodies isolated by KOSSEL and FREYTAG from pus, and called 

 pyosin and pyogenin, also belong to the cerebrosides (see Chapter VII). 

 Cerebrin. Under this name W. MULLER 1 first described a nitrog- 

 enous substance, free from phosphorus, which he obtained by extracting, 

 with boiling alcohol, a brain-mass which had been previously boiled with 

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

 slightly, GEOGHEGAN 2 prepared,, from the brain, a cerebrin with the 

 same properties as MULLER'S, but containing less nitrogen. According 

 to P ARGUS 3 the cerebrin isolated by GEOGHEGAN, as well as by MULLER, 

 consists of a mixture of three bodies, " cerebrin," " homocerebrin," 

 and " encephalin." KOSSEL and FREYTAG isolated two cerebrosides 

 from protagon which were identical with the cerebrin and homocerebrin 

 of P ARGUS. According to these investigators, the two bodies phrenosin 

 and kerasin, as described by THUDICHUM, seem to be identical with cere- 

 brin and homocerebrin. 



Cerebrin, according to PARCUS, has the following composition: C 69.08, 

 H 11.47, N 2.13, O 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 burnt 

 fat, and burns with a luminous flame. 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 consist of a mass of globules 

 or grains on microscopical examination. Cerebrin forms a compound 

 with baryta, which is insoluble in water and is decomposed by the action 

 of carbon dioxide. Cerebrin dissolves in concentrated sulphuric acid, 

 and on warming the solution it becomes blood-red. The variety of 

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

 is, in THIERFELDER'S 4 opinion, galactose. 



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

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

 alin has the composition C 68.40, H 11.60, N 3.09, and O 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 



1 Annal. d. Chem. u. Pharm., 105. 



2 Zeitschr. f. physiol. Chem., 3. 



3 Parcus, Ueber einige neue Gehrinstoffe, Inaug.-Diss. Leipzig, 1881. 



4 Zeitschr. f. physiol. Chem., 14. 



