This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Pharm. Lond. Isinglas or Fish-glue: a solid glutinous substance, prepared from a fish of the sturgeon kind, caught in the rivers of Russia and Hungary. The skin, sins, etc. are boiled in water, the decoction inspissated to a due consistence, and then poured out so as to form thin cakes; which are either exsiccated in that form, or cut while soft into slices and rolled up into spiral, horse shoe, and other shapes. The best is in thin, clear, and almost transparent pieces.
* A different account of the formation of isinglass is given by Mr. Jackson in Philos. Trans. vol. lxiii. part I. He asserts that the solution of animal substances of every kind gives glue, not isinglass; that this last is nothing more than certain membranous parts of fifties, as the air-bladder, intestines, peritonaeum, etc. in their entire state, only freed from their natural mucus and adhering matters, and rolled and twisted into the forms in which we get it.
Ichthyocolla is one of the purest and finest of the animal glues, of no particular smell or taste. Beaten into shreds, it dissolves pretty readily in boiling water or milk, and forms a gelatinous substance, which yields a mild nutriment, and proves useful medicinally in some disorders arising from a sharpness and colliqua-tion of the humours. A folution of it in water, curiously spread, whilst hot, upon silk, affords an elegant sticking plaster for slight injuries of the skin, not easily separable from the part by water, and scarcely inferiour to the more compounded one fold under the name of the ladies black plaster, in which different balsams and resins are joined to the ichthyocolla.