es 
fs) 
@ Q 
) 
5 
"9 
a. 
= 
5 
g 
a 
ct 
n 
Dupin fays, that ‘ There is neler order in his narrative, 
nor correctnefs in his obler vations, nor elegance in his ex- 
matter; fo that he 
a bad compiler who has collected, with- 
out any dif es whatever he found relating to the 
council of Nice, whether good or bad, not examining even “fl 
a 
whether it were true o e.F” Moreri. upin. . 
TIN, or pene JELLY, in Chemiffry;.a prin- 
ciple that abounds in.various parts s of animals, and forms one 
of the elementary conftituents of animal organization. 
principle is copioufly contained in fkin, in moit of the foft 
and white parts, in bone, horns, and membrane, and in a 
{m aller proportion in : 7 ba d, and alfo in many fhells. 
_ From thefe acy ‘be. extracted by boiling. in 
The watery ilation is nearly tranfparent and:.co- 
lourlefs, and cae wed. to evaporate and cool, it aflumes 
(See JELby.) 
3 
i=} 
* Au 
ct 
Bs 
oO 
"2 
3 
a eae ge cme is 
nd nearly colourlefs, “or 
me exhibi ee a rake of yellow. When 
se own into water, it abforbs the water, f{wells,. 
becomes very elattic. 
it be again expofed toa warm. dry air, it thrinks and regains 
its former confiftence. But by the application of heat to 
gelatin, when it is thus fwelled by foaking and immerfed in 
more water, it forms a folution, exactly refembling in chemi- 
-cal qualities a mee from which. the dr gelatin was pre- 
and 
Tn this eae it efieataily difters from Gc folu- 
ing heat. 
saa which Tat. Se py hs ae , and does not 
tion of album 
the ee on upon it 
colour, which. a ecomes 
deeper by evaporation. When mee een the 
acid, acting at firft merely as a folvent, is decompo ed by the 
ometimes attended with 
fi 
new _ produ 
pr as ae ree with any of the alkalies or 
The muriatic acid diffolves gelatin in the cold with great 
eafe, and, like the nitric, feparates it from the denfe albu- 
men of organized bodies, with which it is naturally com- 
bined :—and the muriatic folution will remain unchanged for 
many months. 
The cauftic fixed alkalies very eafily difolv gelatin, and 
form a brownith vifcid ‘ubftance; givin 
§ 
ene the folution, This vifcid a alkaline cee Mr.. 
bulky 
Hiatchett, is 56 grains 
It is not diffolved whilft cold, and: if 
. Boftock found (edinb. Med seis Phyf. J 
Hatchett obfervés,, an not poffefs.the properties of foap, 
for it does not form a permanent lather when. thaken with 
water, and when faturated with acid it affords no precipi- 
tate. [his circumftance, according to Mr. Hatchett, 
affords a very charaéteriflic property, ee otis 
elatin from albumen, fibrin, and moft other foft t parts of 
come . 
with vegetable mucilages and alcohol; but unlefs a a very 
oe quantity of {pirit is added, the mixture again becomes 
lea: 
Hard and dry gelatin ie remain unchanged ree a long 
time; but when liquid,..or in t 4 
{oon putrefies, becoming: firft: four by 
acetic acid, then moulds. and. fetid, ae at lait exhaling am~ 
monia. - 
y gelatin i is very. ml heated, it ie ‘and. be- 
, like all 
tne 
2 * 
: 
ie) 
cineration in open air burns. away. entirely, except 1.5 
earthy gered which appears to be the phofphats ot foda 
and lim Hence i it appears that the quantity of earthy and 
faline are is extremely {mall, compared with that of the 
other foft parts e fame chemift alfo obfe 
artificial oe on of condenfed albumen into gelatin oe 
digeftion in dilute nitric acid ; the albumen the reby be pings 
e in water, and forming a gelatinizing inte 
ed by evaporation. . 
of fingular combination. of gelatin, and that whicly 
Af a fo lution of 
The mo 
is ear ufeful as a chemical teft, is with tan. 
be very ea “aly collected by the fingers, and form 
grey duétile mafs, fmelling like tanned leather, 
runs into a dark brown brittle mafs, appearing like refin, in- 
foluble in water, and incapable of putrefaGtion. For a fur- 
ther account - this eae fee Tan. The power of 
infufion of tan as a gelatin is very extenfive. Dr. 
only -. ‘e of ena. anda 
gelatin 
be confidered as a pretty certain indication of gelatin 
The nitro-muriate of tin produces alfo a white precipie 
tate with gelatin; but unlefs the folution of the latter is 
pretty ftrong, the effe&t is only ‘a: white cloud, after fome 
ours ftanding. a ly the fame effect j is produced with the 
ee _ en 
it obferves, that the difference i in the degree of 
mee and pane ity of the varieties o tin 
rent lity, and not caufed by the degree of mere infpiffa- 
tion; Sie, when each variety was pertectly dry, they 
would each make a glue or cement of exadily the fame de- 
ree of tenacity, which is known not to be the cafe. On. 
the contrary, the tenacity, depends sale on the age of the 
aes the old giving a much ftron r glue, cateris paribus, 
the young; and partly on the {ablanees that —— - 
5 
