The Isinglass of Commerce. 249 



inch, and the best way to see its fibrous structure is to tear 

 it across when it is dry. In this way it spHts in the direc- 

 tion of the transverse fibre, of which nine-tenths of its sub- 

 stance consists, the obHque fibre forming merely a thin 

 coat outside. If the mechanical division of the transverse 

 fibre be thus continued, the outer oblique coat becomes 

 readily detached, and falls off in plates and scales from the 

 outside. Thus, by mechanical means the organ may be 

 separated into two very distinct parts — the first, or trans- 

 verse fibre, consisting of perfectly pure gelatine, comprising 

 about nine-tenths of the whole ; the second, or oblique 

 fibre, falls off in broad plates, consisting of albumen, thus 

 leaving the gelatine or isinglass perfectly pure. 



When cut open, cleaned, and dried as above, the suleah- 

 sound weighs from 12 to 16 ounces, from which 90 per cent, 

 of pure isinglass may be separated by mechanical means. 



The fish being caught at a distance from Bombay and 

 Calcutta, the sounds are usually sold unopened and un- 

 cleaned, as taken from the fish, with the cobweb of blood- 

 vessels hardened and dried upon the surface, which is 

 frequently stained with blood. 



In this state it requires to be soaked for 12 hours in 

 water to overcome the horny consistence, so far as to be 

 able to cut it open. The outer rind, being insoluble, is that 

 on which soaking makes the least impression ; so that 

 when opened we frequently find much of the pure isinglass 

 within dissolved ; and if continued soaking and washing be 

 practised after it is opened, with a view to soften and 

 cleanse the outer insoluble rind, the article may become 

 greatly impoverished and deteriorated from the solution of 

 the inner parts, which thus become dissolved and washed 

 away incautiously during the operation. 



To obviate this it is only necessary to induce the 



