23S 
OK THE ADULTERATION OF ISINGLASS. 
The quality of cut isinglass is estimated, 1st, by its color, 
that which is cut fine by machinery being, ceteris paribus, 
the whitest and generally most esteemed; 2dly, by the 
smell emitted after breathing upon it, that being the best 
which is least disagreeable in this respect ; 3dly, by the 
extent of its solubility in water; and, 4thly, by the con- 
sistence, transparency, and flavor, of the resulting jelly. 
This practical method of examination is that alone by which 
slight shades of difference may be discovered, yet a differ- 
ence of flavor which only a practised palate, or careful compa- 
rison with an approved specimen, could detect, is often impor- 
tant in an article intended for the diet of the fastidious invalid, 
and a slight superiority in this respect, will, therefore, com- 
mand a much increased price. 
There is no substance that affords so pure and good a 
jelly as the best Russian isinglass ; but gelatinous substances 
are obtained from other sources, and for several years past 
have been sold as substitutes for isinglass under the name 
of gelatine. The gelatines of commerce are prepared, 
either from the skins of animals, or from bones. The jelly 
made from some of these substances is nearly as firm as that 
made from isinglass, and although it has more or less of a 
sickly flavor, sometimes strongly resembling that of glue, 
yet it must be admitted that the manufacture of gelatine, 
especially that made from bones, has been greatly improved, 
so that in color, solubility in water, and gelatinising power, 
it is almost equal, although in flavor decidedly inferior, to 
the best isinglass. The sheet gelatine is sold, wholesale, at 
fifteen pence a pound. 
Solutions of good gelatine, and those of isinglass, give 
similar reactions with the tests usually employed in the ex- 
amination of gelatinous substances ; it became necessary, 
therefore, to find some characters, other than those usually 
relied upon, by which to detect the presence of gelatine when 
mixed with isinglass. 
Specimens of the best Beluga leaf and staple isinglass, 
