isinglass, a preparation from the fish known by the name of huso. See **ACCIPENSER**.

This is a tough and firm substance, of a whitish colour, and in some degree transparent; it is light, moderately hard, very flexible, and of scarce any smell, and very little taste. We usually receive it in twisted pieces of an oblong and rounded figure, and bent in the shape of a horse shoe: this our druggists usually beat and pull to pieces, and sell it in thin shreds like skins, which easily dissolve: besides this kind of round isinglass, we meet with some in small thin square cakes, white and very transparent; these are the finest of all. But isinglass, of whatever shape, is to be chosen clean, whitish, and pellucid.

The method of preparing the ichthyocolla is this: they cut off all the fins of the huso, close to the flesh, and take out the bladder, stomach, and intestines; they wash these very clean, and then cut them in pieces, and throwing them into a large quantity of water, they let them steep four and twenty hours, and after this they kindle a fire under the vessel, and keep the liquor just boiling till the greater part of the matters are dissolved; they then stir the whole briskly about; then strain it through flannels, and set the liquor by to cool. When there is a large quantity of fat usually formed upon it, which is carefully skimmed off, and the clear liquor is poured off from the groser parts which subside, it is put over the fire again, and gently evaporated and skimmed afresh all the time, till by trials they find, that on letting a spoonful of it cool it will harden into the consistence of glue. Great care is taken to keep the fire very gentle, to prevent burning towards the end of this evaporation. They then pour it out upon a large smooth, wooden table; and as it cools, form it into the masses we meet with it in, by cutting and rolling it up.

The greatest quantity of isinglass is made in Russia. We have it principally from Holland, the Dutch contracting for the mott of it before it is made.

It is an excellent agglutinant and strengthener; and is often prescribed in jellies and broth, but rarely enters any compositions of the regular medicinal form. It is the most efficacious as well as the most safe and innocent of all the ingredients used for cleaning wines, upon which account the wine-coopers use a much greater quantity of it than the apothecaries.

A very valuable glue is also made of this drug, which is a proper form to keep it for the wine-coopers use.