240 
ON THE ADULTERATION OP ISINGLASS. 
very slight flocculent precipitate will be deposited, which, in 
operating on twenty or thirty grains of the isinglass, will be 
scarcely perceptible. 2. If cut gelatine be macerated in 
cold solution of caustic potash, it will become opaque ; even 
those specimens which were so, to a certain extent, previ- 
ously, will assume increased opacity after their immersion. 
The gelatine will ultimately dissolve, as does the isinglass, 
but the solution will not be transparent, and after standing 
for some time, a copious flocculent precipitate will be de- 
posited. 
Inorganic constituents of Isinglass and of Gelatine. — 1. 
On carefully incinerating isinglass in a platinum crucible, an 
ash of a reddish color is obtained, amounting to .5 per cent., 
(| a grain in 100.) This ash consists principally of carbo- 
nate of lime. 2. On incinerating gelatine, as above de- 
scribed, a voluminous white ash is obtained, amounting to 
3. per cent., (3 grains in 100.) This ash, like the former, 
consists principally of carbonate of lime. Three per cent, is 
the smallest amount of ash obtained from any of the speci- 
mens of gelatine operated upon, but some specimens yield 
more . 
Having thus ascertained that there are several characters, 
besides those of taste and smell, by which isinglass may be 
distinguished from commercial gelatine, I proceeded to ex- 
amine a specimen of isinglass obtained from the same source 
as that referred to in Mr. Warrington's report, and which 
was suspected to be adulterated. 
1. A portion of the specimen was macerated in cold water. 
After standing for about two hours, the swelled and softened 
shreds were examined under the microscope with a low 
power, and they were found to consist partly of an opaque 
fibrous substance, resembling genuine isinglass, and partly of 
transparent flakes, resembling gelatine. In some of the 
pieces these substances were seen to form distinct strata, 
running parallel to each other; but in others they were more 
confusedly interstratified, or the strata completely broken, 
