THE CEREBRINS OR CEREBROSIDES. 
The percent; i :4c composition is seen in bhe following table: — 
119 
Elements. 
LlEBRBll U. 
IMGEE AND 
!'.!. INKEN'nORN. 
18TARK. 
KO£ • 
RUPPEL. 
( '\I.< PLATED 
PROM 
Formula. 
< IX. 
Human. 
C 
H 
N 
P 
S 

66-74 
11-71 
2 -SO 
1-23 
66-39 
10-69 
2-39 
1-068 
19-462 
66-48 
11-12 
2-35 
1-02 
18-701 
66-25 
1113 
3-25 
0-97 
0'51 
66-29 
10-7.". 
2-32 
11 3 
0-096 
66-51 
10-88 
2-55 
1-138 
66-45 
10-66 
2 "42 
T07 
19-40 
An elaborate research by Thudichum 1 led him to the conclusion that 
there are three groups of phosphorised substances in the brain, which he 
termed kephalines (very soluble in ether), myelines (less soluble in 
ether), and lecithins (characterised by their extreme instability). In 
each of these ill-defined groups several members with their empirical 
formulae are described. Thudichum's work has been so far confirmed 
by that of Kossel, in that he has shown that protagon is not a single 
substance, but that there is mure than one protagon. They yield either 
one or two or perhaps three derivatives (cerebrosides), called eere- 
brin, kerasin or homocerebrin, and encephalin ; and, further, probably 
several lecithins are obtainable from the different protagons. The 
constitution of lecithin is discussed on p. 22, and there it will be seen 
that the existence of several lecithins (i.e. containing different fatty acid 
radicles) is mooted. The protagons, according to Kossel, resemble each 
other in the following points : — 
1. They contain carbon, hydrogen, nitrogen, oxygen, and phosphorus. 
Elementary analysis gives practically the same results as those obtained 
by other observers. But the existence of sulphur in some varieties of 
protagon is a new point. 
2. By oxidation with nitric acid they yield higher fatty acids (palmitic 
and stearic). 
3. By the action of boiling sulphuric or hydrochloric acid a reducing 
carbohydrate is formed. 
4. By the action of alkalis they yield cerebrosides (formerly called 
cerebrins). 
5. The cerebrosides are the source of the reducing carbohydrate 
mentioned above. 
G. The carbohydrate formed is galactose. 
7. Other decomposition products of the cerebrosides are ammonia, and 
a complex material which on fusion with potash yields higher fatty acids. 
The cerebrins or cerebrosides.— These substances, the glucoside 
constitution of which has just been alluded to, form a group of ill- 
defined, nitrogenous substances, existing especially in the white sub- 
stance of nervous tissue, and also in the yolk of egg, pus corpuscles, 
and spleen cells. 2 
1 Rep. Med. On. Privy Council, London, 1874, |>. 11-3 et seq. 
- Hoppe-ScyleV, "Physiol. Chem.,"' S. 720, 788. 
