98 Production of Isinglass on the Coasts of India. 



Chemical and Essential properties. The author sent specimens to 

 Mr. Hennel of Apothecaries' Hall, which he was good enough to 

 examine. He complains of it as being insoluble, very closely resem- 

 bling the Brazilian Isinglass, and therefore of low value. As the 

 article promises to be of considerable importance as an export from 

 India, it was desirable to have it submitted to a detailed and careful 

 Chemical analysis. Mr. Edward Solly, jun., Lecturer on Chemistry 

 at the Royal Institution, has furnished the following account of the 

 results of his experiments. 



NOTE ON BENGAL ISINGLASS. 



Good Isinglass is generally described as being one of the purest 

 forms of Gelatine we are acquainted with ; it consists, in fact, of 

 little else besides, and accordingly presents very nearly the charac- 

 ters of that substance. The properties of pure Isinglass or Gelatine 

 are briefly the following. It is transparent and colourless, or nearly 

 so, inodorous, tasteless, and of a hard or horny consistence. It is 

 but little hygrometric, remaining tolerably dry in ordinary conditions 

 of the atmosphere. In cold water, it gradually softens and swells 

 up ; in hot water, it easily dissolves, and forms a clear solution, which 



if it contain as much as a __L th part of its weight of Gelatine, has 



100 



the property of gelatinizing or assuming the form of a soft tremulous 

 solid as it cools. Dry Gelatine is a permanent and unchangeable 

 substance, but in solution it is very liable to undergo decomposition, 

 becoming mouldy, and rapidly putrifying when exposed to the air ; it 

 has been observed that the ordinary and more impure forms of Gela- 

 tine are more liable to undergo these changes than the pure sub- 

 stance, the presence of minute quantities of acids, alkalies, and other 

 impurities, greatly accelerating its decomposition. All Isinglass 

 contains small quantities of Albumen, Saline, and earthy matter, and 

 a peculiar substance called Ozmazome, the better sorts containing 

 less, and the inferior more of these impurities. 



The Bengal Isinglass consists of Gelatine, Albumen, a small por- 

 tion of saline and earthy substances, Ozmazome, and a minute trace 

 of an odorous oil. The Albumen exists in an unusually large pro- 

 portion, which of course somewhat modifies the properties of the 

 Isinglass. The pieces are rather unequal in composition, some of 



