102 Production of Isinglass on the Coasts of India. 



glue, that is of Gelatine, as it would now be called. He describes 

 the Sounds as taken from the fish while sweet and fresh, slit open, 

 washed from the slimy sordes, divested of a very thin membrane 

 which envelopes the Sound, and then exposed to stiffen in the air. 

 He also details the mode of making, and gives figures of the long 

 and short staple, and of the book form of Isinglass. 



The Sounds of the Cod and Ling, he states, bear great analogy 

 to those of the Sturgeons ; and that they had been prepared and 

 employed as substitutes for the foreign Isinglass in fining, and 

 with similar effects, except in warm weather. The only peculiarity, 

 he describes in their preparation is, that when the Sounds are slit 

 open, they are washed in lime water, in order to absorb their oily 

 principles ; and then in clean water, when they are laid upon nets 

 to dry. He also states, that since this discovery, and before the 

 publication of his paper, forty tons of British Isinglass had been 

 employed; also that several specimens of fine Isinglass had been 

 obtained from North America, in consequence of advertisements 

 distributed in different parts, offering premiums for the Sounds of 

 Sturgeon and other fish. In this we may probably trace the origin 

 of the American trade in Isinglass. 



The several distinguished naturalists who were employed by the 

 Russian Government in exploring the different parts of that exten- 

 sive empire, have collected valuable information on this, as on many 

 other subjects. This we find incorporated in several works, as in 

 Tooke's View of Russia, published in ] 799, and in the recent one 

 of Brandt and Ratzeburg (v. p. 17). 



Brandt and Ratzeburg describe the swimming-bladder as consist- 

 ing of three membranes, the outer or peritoneal coat, the middle 

 membranous and muscular one, and the inner glossy highly vascular 

 one, which has a pulpy appearance, and is the membrane which 

 forms the best Isinglass. The species which yield it are the Great 

 Sturgeon, Osseter, Sevruga, and Sterlet, also the Silurus Glanis, 

 Barbel, and Perca luciopenca, Cyprinus Brama and Carpio, which 

 do not belong to the tribe of Sturgeons. 



In the fisheries of the Caspian and Volga, where the system 

 is most complete and the division of labom- the greatest, the 

 Sounds and Roes are extracted immediately the fish are caught, 



