Collodium is a solution of pyroxylon in ether or alcohol. It is prepared by taking pyroxylon, 1 ounce; ether, 36 fluid ounces; and rectified spirit, 12 fluid ounces; mixing the two latter, and allowing the pyroxylon to dissolve in them.

1 American Journal of Med. Science, 1841; Charleston Med. Journ., xi 118.

The formula is C26H12(NO48)O10.

Collodion is a colorless, inflammable fluid, having an ethereal odor, and rapidly drying upon exposure to the atmosphere. When the drying is complete, pyroxylon is left as a transparent film, insoluble both in water and rectified spirit.

This property allows it to be usefully employed in cases of cracked nipple, fissures of the anus, superficial ulcers of various kinds, and superficial burns and wounds, to all of which it forms a protective covering. The same with erysipelas; and as a stopping, applied upon cotton, for carious teeth: it forms likewise a very excellent application to slight cuts, such as are made by a razor while shaving.

Preparations. - Collodium flexile; collodium cum cantharide.