NERVOUS SYSTEM. (Nervous Marrer.) 
stance of extreme softness and delicacy, liable 
to break up under the least pressure; the 
nervous tissue owes much of its physical tena- 
city to the other tissues which are associated 
with it, and to the numerous bloodvessels 
which play among its elements. 
The chemical composition of this matter has 
been an object of investigation with several 
observers, but it is remarkable that few com- 
parative analyses of the two kinds of ner- 
vous matter have been made with a view to 
determine on what the differences hetween 
them depend ; and, indeed, such an analytical 
investigation is as yet a great desideratum. 
The part which has chiefly been selected for 
analysis is the brain, in which doubtless both 
kinds of nervous matter were indiscriminately 
examined. 
Among the earliest investigations of this kind 
were those of Leming; some time afterwards 
Thouret examined the brain; and still later 
Fourcroy. The last writer notices the large 
admixture of water with the cerebral substance, 
and points it out as one of those animal sub- 
Stances in which water exists in the largest pro- 
ttion; from constituting, as it does, three- 
urths or four-fifths, and in many instances 
seven-eighths of its weight. Vauquelin’s ana- 
lysis, made in 1812, gave a considerable insight 
into the true composition of the brain. This 
chemist showed that the cerebral substance is 
an emulsive mixture of albumen, fatty matter, 
and of water, the last holding in solution certain 
Saline and other ingredients common to the 
brain with other parts of the body. By solu- 
tion in boiling alcohol, Vauquelin was enabled 
to obtain the two constituents of the fatty 
substance, namely, the elaine and stearine 
(margarine). Vauquelin also recognised the 
ime of phosphorus in the brain. His ana- 
ysis yielded the following result: — 
PTT aviaiss d' evs dese! siceese. 7.00 
. ¢ stearine ..4 53) 
Cerebral fat.... Velaine,...0.70§ °°°° 9°23 
SPL S FUcle ss oss veces 1:50 
mMazome .......... SO ae eoee 1.12 
Acids, salts, sulphur ..........2.0006 515 
PeMeP oss... 
100.00 
John, who specially analysed the grey ner- 
vous matter, states that it is deficient in fatty 
Matter, and that its albumen is less tenacious 
than that of the white. | And Lassaigne states 
that the grey substance is deficient in white 
fatty matter, but contains a greater proportion 
of red, 3.7 per cent. being the amount con- 
tained in the grey, and 0.9 per cent. in the 
white.* 
Vauquelin remarks that the medulla oblon- 
gata and the medulla spinalis have the same 
composition as the brain, but contain a much 
greater quantity of cerebral fat, with less albu- 
men, Osmazome, and water. 
M. Couerbe’s elaborate analysis does not ap- 
pear to be entitled to much confidence, since the 
* Valentin Repert. 1837, p. 186. 
587 
compounds into which he resolved ‘ cerebral 
matter did not, on analysis, always present 
the same composition. ‘This variation of ele- 
mentary constitution he attributed to physiolo- 
gical differences in individuals. 
The latest and apparently the most complete 
analysis of the brain is that by Fremy, pub- 
lished in the Annales de Chimie for 1841. 
In the main his results agree with those of 
Vauquelin. 
He states that the cerebral mass is formed, 
as had been already shown by Vauquelin, of 
an albuminous matter containing a great quan- 
tity of water, and which is found mixed with 
a peculiar fatty matter; and that these different 
substances exist in the following proportions, 
seven parts of albumen, five parts of fatty 
matter, and eighty parts of water. 
The chemical examination of the albuminous 
matter yields nothing of importance. This sub- 
stance is insoluble in water, in alcohol, and in 
ether. M. Fremy’s principal care has been to 
determine the composition of the fatty matter, 
and this he has endeavoured to do by an ana- 
lysis of the brain in different animals, but prin- 
cipally in man. 
His method of proceeding is, to cut the brain 
into small pieces, and to treat it with successive 
portions of boiling alcohol,leaving them forsome 
days in contact with the spirit. The object of 
this is to remove from it its large quantity of 
water, which interferes with the action of ether 
upon it. The coagulated mass thus obtained 
is submitted to pressure, is divided rapidly in 
a mortar, and is then treated by ether, first cold 
and subsequently hot; the resulting fluids when 
submitted to distillation yield a viscid residue, 
which is called the ethereal product. 
The principles which he extracts from the 
brain by this method, are—1. a white sub- 
stance called cerebric acid; 2. cholesterine ; 
3. a peculiar fatty acid called oleophosphoric ; 
4. traces of elaine, margarine, and fatty acids. 
These principles are not always found in an 
isolated state; for the cerebric acid is often 
combined with soda or phosphate of lime; and 
the oleophosphoric acid is commonly found in 
the state of a salt of soda. 
Cerebric acid, when purified, is white, and is 
in the form of crystalline grains. It dissolves 
without residue in boiling alcohol, is almost 
insoluble in cold ether, more soluble in boiling 
ether, It has the remarkable property of swel- 
ling up, like starch, in boiling water, but ap- 
pears to be insoluble in that liquid. It enters 
into fusion at a high temperature, approaching 
closely that at which it is decomposed, and is 
combustible. It contains no sulphur, but some 
aoe gta The result of its analysis by 
remy is 66.7 per cent. ofcarbon, 10.6 of 
hydrogen, 2.3 of nitrogen, 0.9 of phosphorus, 
19.5 of oxygen. 
Oleophosphoric acid is separated from cere- 
bric acid by its solubility in ether. It is still 
accompanied by elaine and cholesterine, which 
are withdrawn from it by alcohol and ether. 
This acid is of a viscid consistence, insoluble 
in cold alcohol, but dissolving readily in boil- 
ing alcohol; it is insoiuble in ether. Placed 
