Of-THE Jelly, Gi.ue, See. —The membranes, ten¬ 
dons, aponeurofes, cartilages, ligaments, and (kin, con¬ 
tain in general a mucous fubdance very foluble in warm 
water, but ihfoluble in alcohol, known by the name of jelly. 
To form a jelly by way of experiment, take one or more 
■of the animal fubdances mentioned above, as calf’s foot or 
any other ligament; boil it over a flow fire, ftrain, and 
evaporate till it becomes a tremulous mafs by cooling } 
to render the jelly more tranfparent, it may be clarified 
with the whites of eggs. A ftronger degree of evapora¬ 
tion a (fords a dry, brittle, tranfparent fub (lance, known 
by the name of glue. 
Glue is prepared with all the white parts of animals; 
the (kin, the cartilages, and the feet of oxen, are ufed to 
prepare the ftrong glue of England, Flanders, Holland, 
.&c. The (kins of eels afford the bafe of gold fize, and 
with old white leather gloves and parchment, a kind of 
glue u(ed by painters, &c. is made. There are fcarcely 
any animals, whofe tendons, cartilages, nerves, and more 
efpecially the (kin, will not ferve to prepare thefe different 
kinds of glue. It mud be here obferved, that glues dif¬ 
fer from each other in their confidence, tafte, fmell, and 
folubility : there are fome which readily become foft in 
cold water, others are not diflolved but in boiling water. 
The bed glue is tranfparent, of a yellowilh brown colour, 
without fmell and tade, entirely foluble in water, with 
which it forms a vifeid uniform fluid, that preferves an 
equal degree of tenacity and tranfparency in all its parts 
as it dries. 
Animal jelly does not differ from glue properly fo 
■called, but in its poffefling a lefs degree of confidence 
and vifeidity. The fil'd is more efpecially obtained from 
the foft and white parts of young animals ; it is likewile 
found in their flefli, mufcles, (kin, and bones. Glue is 
obtained only from animals of a greater age, whofe fibres 
are dronger and drier. Thefe two fubdances, however, 
exhibit the fame chemical properties ; and therefore we 
sfhall (peak of the jelly afforded by the cartilages or mem¬ 
branes of veal. 
In its natural date, jelly has no fmell, and but a faint 
tade : by didillation in the water bath, it affords an infipid 
..and inodorous phlegm, capable of putrefaCtion ; in pro¬ 
portion as it lofes its water, it affumes the confidence of 
glue, and, when entirely dried, it refembles horn; when 
expofed to a dronger fire, with accefs of air, if (wells, 
liquifies, and becomes black, emitting an abundant 
fume, of a fetid fmell; it does not take fire without ex- 
pofure to a violent heat, and even then not readily ; by 
.didillation in a retort, it aflords an alkaline phlegm, an 
empyreumatic oil, and a fmall quantity of ammoniacal 
carbonat ; it leaves a large mafs of charcoal, difficult to 
incinerate, which contains muriat of loda and calcareous 
rphofphat. 
Jelly, when expofed to a hot and moid air, becomes 
fil'd acid, and foon after putrid. Water diffolves in it 
all proportions ; acids, and efpecially alkalis, diflolve it 
readily. By diffolving glue or ifinglafs in warm water, 
and pouring an infufion of nut-galls into the folution, 
a precipitate is obtained. Acids readily diffolve jellies 
and glues. With nitric acid, glue is converted into ox¬ 
alic acid, and difengages azotic gas. Alkalis diffolve 
i jelly entirely. 
Of the Brain. —This fubdance, whofe nature is fo 
little known, merits fome attention from the chemid. 
To preferve it, it (hould be kept in a veffel with alcohol. 
In a certain time it becomes faturated, takes a difagree- 
able fmell, and depofits little needles, which feem to be an 
adipo-ferous fubdance, fimilar to the white of whale, im¬ 
properly called lpermaceti. Water does not entirely dif¬ 
folve brain; awhitifli matter always remains at the bottom. 
Thouret has written at fome length upon the fubdance 
of the brain. He confiders the white of whale to be one 
of its condituent principles, and one of the mod natural 
elements of the animal economy. He fays' it is mingled 
in a certain proportion with the lymphatic juices of all 
i 
parts of the body; and, being depofited in a membrane 
or net of a particular texture forms the bafis of the brain. 
Fourcroy has analyfed the brain of feveral animals s 
his memoir on that fubjeft is in the 16th vol. of the An - 
nales de Ckimie. He has demondrated by experiment, 
that befides the animal pulp, or bafis, it contains phof- 
phats of lime, ammoniac, and foda, in very fmall pro¬ 
portions ; that it contains no uncombined alkali, as fome 
chemids have afferted, and not an atom of potafli. As 
to the formation of the pulp or bafis of brain, Fourcroy 
is of opinion, (quite contrary to Thouret before cited,) 
that among all animal organs it forms a clafs, or rather 
genus, entirely didinCl from all other matter. Experi¬ 
ments have now confirmed this affertion beyond difpute; 
they prove efpecially, that it has the lead analogy with 
white of whale; and that it differs greatly from the al¬ 
bumen of the blood, though it refembles this perhaps 
more than it does any other animal fubdance. 
The ’vitreous humour of the eye is perfectly foluble in 
water; but the cryflalline coagulates, becomesopake, and 
hard. 
Of the Muscular Organs. —The mufcles are red 
in certain animals, white or grey in others. The flefliy 
parts are lean in fome animals, fat in others. The an¬ 
cient chemids, as Geoffroy, &c. though they made many 
experiments on thefe fubdances, have left us nothing fa-* 
tisfa&ory. Fourcroy, whom we have fo often quoted in. 
this treatife, has dilcovered, befides gelatin, albumen, 
and fibrin, a fourth component, which is fat. Bertholiet 
had the fame refults. 
By wafliing a mufcle in water, from red it becomes 
white ; the colouring part unites with the water ; by this 
means, the gelatin, albumen, and extractive matter, may 
be feparated. The red liquid drawn out by expreffion, 
is fimilar to the clot of blood waflied and exprefied. It 
is a very bad method to wafli the mufcular parts in water, 
previous to making broth. If the refidue of the lixivi- 
ation be treated with alcohol, a peach-coloured precipi¬ 
tate will be thrown down; the alcohol retains only (ome 
portions of fait, either muriat of foda or of potafli, and 
the extractive matter; which lad is feparated by evapora¬ 
tion. Boil the flefli which has undergone thefe two ope¬ 
rations in water; by ebullition the gelatinous part is dif- 
folved, and it takes away alfo the portions of extraCl and 
of (alt, which efcaped the aCtion of the firfi folvents. By 
(lowly evaporating the water fil'd employed, without heat, 
the albuminous part coagulates, and is leparated by the 
filter, and the faline matter may be obtained by a fuc- 
ceeding evaporation; the alcohol likewile being evapo¬ 
rated, affords the coloured extractive matter; and ladly, 
the decoCtion affords the jelly and the fat oil which fwims 
at the furface, and fixes by cooling. After the extrac¬ 
tion of thefe different fubdances, nothing remains but 
the fibrous matter, which is white, infipid, inloluble in 
w'ater, contracts and curls up by heat, and by didillation 
in a retort, afibrds much ammoniac, and a very fetid oil. 
A large quantity of azotic gas is obtained from this fub- 
ltance by the aCtion of the acid of nitre. In a word, it 
pofleffes the characters of the fibrous part of the blood ; 
it therefore appears to be proved, that the mufcular or¬ 
gan is the refervoir, in which the aCtion of the vital 
powers depofites the fibrous matter, which becomes con¬ 
crete by red; and which appears to form the bafis of 
that animal property which phyfiologids call irritability. 
When flefli is boiled in water, the albumen coagulates 
and rifes to the furface, this is called feum ; the (aline 
parts, which remain in the water, and the gelatin and 
fat which coagulate when cold, conflitute broth or fov.p. 
For a lighter kind of Coup, boil the meat as long as is 
neceffary, and then drain through a cloth ; a great deal 
of the fat will be left behind. Evaporate this well-drain¬ 
ed broth over a water-bath, and a (olid jelly is produced, 
called gravy cakes, or folid broth. Thefe cakes may be 
enriched with chickens, aromatics, &c. they are tome- 
times alfo made from herbs. 
Lime- 
