58 
ON ISINGLASS. 
efficient; so that there would not appear to be any obstacle 
to the article becoming an important production. In its re- 
fined form it is identical, in all its properties, with Chinese 
camphor. 
Calcutta Journal of Natural History. 
ART. XVII.-ON ISINGLASS. 
Avery important observation has been made relative to 
the structure of the air vessel of Polynemus SiM, which 
will lead to the perfect purity of the isinglass, and place it 
on a footing with the best Russian description of the article ; 
while the abundance in which it is afforded by this fish 
cannot fail to render it an object of great importance. When 
examining a sample of the article received from Mr. O'Rei- 
ley, of Amherst, weighing 12 lbs., and which cost on the 
Tenasserim Coast 4 rupees, it was found that each piece, 
from which the outer and inner membranes are removed, 
consists of an outer and an inner structure. The outer struc- 
ture consists of a thin lamina, composed of oblique fibres, 
which are easily seen passing diagonally over the surface, 
and composing about ten per cent, of the whole. If the 
mass be divided crosswise into narrow sections, the trans- 
verse fibres maybe perfectly separated into fine silky fibres, 
which consist entirely of pure isinglass. Mr. Scott, the As- 
sistant, who was employed in the examination, suggested 
the separate analysis of the outer oblique fibres, when it 
was found that they consisted entirely of fibrin, and con- 
tained all the impurities for which the Bengal isinglass had 
hitherto been considered inferior. 
Comparing one of the sections from which the oblique 
fibres had been removed, (No. 5 in the annexed table,) with 
a specimen of isinglass received form Dr. Royle, (No. 1 in the 
annexed table,) and said to be very pure, the resemblance 
was quite perfect, and it will be seen from the annexed 
table of analysis that, of the two, our own specimen is the 
