To make isinglass, the air-bladders are washed carefully in water, and the outer membrane is removed; what remains is then rolled up in a cloth, and kneaded with the hands, until it has become thoroughly softened. Each bladder is then moulded into a cylindrical form, dried in a gentle heat, and bleached with the fumes of brimstone.

The Common Sturgeon has the snout slender and pointed; the body is somewhat five-sided, being studded with five rows of bony plates, that run down the whole length; one along the back, another along each side, and two more bordering the belly. These plates are oval, with a curved spine in the centre of each. The ground colour of the body is brown on the upper parts,