248 The Commercial Products of the Sea. 



dried in the best manner. . . . Isinglass cut into threads 

 is unsuitable for the English market, because there is a 

 great prejudice against purchasing wholesale, things in a 

 cut and powdered state, in consequence of the innumerable 

 methods adopted for falsifying and adulterating almost 

 every drug." 



The method adopted in separating isinglass from the 

 fish-sounds and rendering it fit for market in India is as 

 follows : 



The air-vessel is from 8 to 12 inches long, pointed at 

 each end like a double nightcap, hollow, but without an 

 opening. It is merely taken out of the fish when caught, 

 and thrown aside without further trouble by the fishermen. 

 It is at first soft and doughy to the feel, and partially 

 distended with air ; but in time it becomes collapsed and 

 hard outside, in which state it is sold to the Chinese. 



When fresh taken from the fish, it is covered by a thin 

 cobweb of small blood-vessels, which are easily peeled off, 

 as none of them enter the substance of the organ. Where 

 this is neglected it is stained and spotted with blood, and 

 the whole becomes hard and consolidated together, or the 

 vascular membrane itself becomes putrid in places. 



Hence the vascular membrane should always be care- 

 fully peeled off the first thing by the fishermen, when the 

 outside will present an appearance like white satin, of a 

 fine, oblique fibrous texture. The edge should now be 

 slit open, and the same kind of bloody cobweb peeled from 

 within. The inner side will then present the same white- 

 satin appearance as the outside, but, if attentively ex- 

 amined, will be seen to consist of transverse instead of 

 oblique fibres. If it be allowed to dry, the whole becomes 

 hard, horny, and partially transparent. 



The thickness of the organ is about one-third of an 



