The air-bags, or sounds, of several kinds of fishes, washed, dried, and otherwise prepared. They are either dried without opening (purse, pipe, and lump isinglass), or opened and not folded (leaf and honeycomb isinglass), or folded (book isinglass), or twisted into the shape of a lyre or horse-shoe (short and long staple). The picked or cut isinglass of the shops, consists of the lumps of stable isinglass, picked in shreds by women and children, or cut by machines. The leaf isinglass is sometimes rolled out into thin plates (ribbon and rolled leaf isinglass). The inner membrane, which is insoluble, is removed, from the opened air-bags, in the best kinds. The Russian isinglass, which is most esteemed, is made from the air-bags of several species of Acipenser (sturgeon ); particularly A. Huso (the Beluga); A. Guldex-stadth (the Osseter); A. Buthenus (the Sterlet); A. Stellatus (the Sewruga); and also from the Silurus glanis (the Som), which yields the Samovey isinglass. Brazilian and East India isinglass are of inferior quality; it is not certainly known from what genera or species of fish they are obtained. New York isinglass is the air-bladder of the common hake, macerated in water and rolled out into ribbons. The sounds of the cod yield an inferior kind. Prepared sole skins are used as a cheap substitute for isinglass. See Dr. Pereira's ' Elements,' for the description of each variety.