ON THE ADULTERATION OF ISINGLASS. 
241 
and only patches of the transparent part appearing here and 
there. In some of the pieces the separate strata could be 
distinctly seen with the naked eye. 
2. Some of the specimen was macerated in cold solution 
of caustic potash. It became less transparent than genuine 
isinglass would be under similar circumstances. After al- 
lowing it to stand for some hours, it dissolved, forming a 
slightly turbid solution, from which a flocculent precipitate 
was deposited, which was much greater than that formed in 
genuine isinglass. 
3. Some of the specimen was incinerated; it yielded an 
ash whiter and more voluminous than that of genuine isin- 
glass, amounting to 1.5 per cent., (I| grains in 100.) This 
ash consisted principally of carbonate of lime. 
It was evident from these results that the specimen under 
examination consisted of a mixture of isinglass and gelatine, 
and the optical examination showed that the two substances 
had been worked together in a manner well calculated to 
elude detection. I felt satisfied, and Mr. Warrinsfton had 
previously expressed the same conviction, that sheet gelatine 
had been rolled between two sheets of isinglass, in the mois- 
tened state, so as to form a ribbon, in which the two sub- 
stances would be united. 
In order to get further evidence in confirmation of this 
view, I applied to Mr. \ ickers, proprietor of the house of 
Simpson & Humphrey, of Little Britain, who is an extensive 
manufacturer of cut isinglass, and who having been a suf- 
ferer from being undersold by the manufacturers of the adul- 
terated article, expressed a willingness to render me any 
facility that his manufactory could afford for elucidating the 
subject. I accordingly had some genuine isinglass and sheet 
gelatine in the proportion of three parts of the former and 
one of the latter, rolled into ribbon and cut, under my in- 
spection. The specimen thus prepared could not be distin- 
guished by the eye from the best Russian isinglass. It agreed 
entirely with the adulterated article met with in commerce,; 
20 
