CEREBROSIDES. 609 



Sphingomyelin, is a diaminomonophosphatide which THUDICHUM prepared 

 from the brain and is the chief phosphatide obtainable from the impure protagon 

 mixtures. ROSENHEIM and TEBB obtained it, as above mentioned, from the 

 protagon. It has been given the formula CsaHNnNaPOg-fH^O. As cleavage 

 products an alcohol, sphingol, neurin, cholin, according to ROSENHEIM and TEBB, 

 the base sphingosin (see cerebron) and sphingostearic acid have been' obtained. 

 Sphingomyelin is soluble with difficulty in cold alcohol but readily soluble in hot 

 alcohol and crystallizes therefrom in needles. It is insoluble in ether. In regard 

 to the specific rotation see above in reference to protagon. Amidomyelin (Thud- 

 ichum) is another diaminomonophosphatide of an unknown constitution and of 

 an uncertain composition. Its existence is uncertain. 



Sahidin was found by FRANKED in the brain, and is a triaminodiphosphatide, 

 whose cadmium compound has the formula CsoHieyNsPzOio.SCdCL. It is a crys- 

 talline powder which is insoluble in water, cold ethyl or methyl alcohol and in 

 ether. It is soluble with difficulty in warm alcohol but readily soluble in chloro- 

 form and hot benzene. It yields saturated and unsaturated fatty acids, choline 

 and glycerophosphoric acid. 



Leucopoliin is an unsaturated phosphatide found by FRANKEL and ELIAS 2 in 

 the brain and which is a decaminodiphosphatide or a pentaminomonophosphatide. 

 It crystallizes from boiling alcohol on cooling. It does not contain any methylated 

 base but does contain a carbohydrate group. 



Sulphatide is the name given by KOCH 3 to a sulphurized and phosphorized 

 product obtained from the human brain which separates from warm pyridine 

 on cooling as a crystalline, granular mass. It contains phosphatide, sulphuric 

 acid and cerebroside and is claimed to be phosphatidesulphuric acid cerebroside. 



Cerebrosides. 



On decomposing protagon (or the protagons), or the brain substance 

 by the gentle action of alkalies we obtain, as cleavage products, as above 

 stated, one or more bodies which THUDICHUM has embraced under the 

 name cerebrosides. The cerebrosides are nitrogenous substances free 

 from phosphorus, which yield galactose on boiling with dilute mineral 

 acids. With concentrated sulphuric acid they first give a yellow and 

 then a purple-red coloration. With sulphuric acid and cane-sugar 

 they give a purple coloration directly. The cerebrosides isolated from 

 the brain are cerebrin, homocerebrin, phrenosin, kerasin, encephalin, 

 and cerebron, but it must be remarked that there is no doubt that 

 sometimes the same body of varying purity has received different names. 

 According to LEVENE and JACOBS 4 it must be admitted that the cere- 

 brosides are mixtures of stereoisomeric substances. 



Cerebrin. Under this name W. MuLLER 5 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 



1 Bioch. Zeitschr. 24. 



2 Frankel and Elias, Bioch. Zeitschr. 28. 



3 Zeitschr. f. physiol. Chem. 70. 



4 Journ. of biol. Chem. 12. 



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



