Prep. Pyroxylin, one ounce; ether, thirty-six fluid ounces; rectified spirit, twelve fluid ounces. Dissolve the pyroxylin in the ether, mixed previously with the rectified spirit.

Prop. & Comp. A colourless highly inflammable liquid with ethereal odour, which dries rapidly upon exposure to the air, and leaves a thin transparent film, insoluble in water and rectified spirit.

Use. Collodion, when applied to the skin, leaves, on the evaporation of the ether, a thin transparent layer, and may be used to cut and inflamed surfaces, in skin diseases, and chapped nipples, to arrest haemorrhage from leech-bites, etc.: in some of these cases it acts by forming a protecting surface; in others, through the contraction of the film constricting the vessels of the part.