. A solution of pyroxylin in ether and alcohol.

Characters. - A colourless, highly inflammable liquid with ethereal odour, which dries rapidly on exposure to the air, and leaves a thin transparent film, insoluble in water or rectified spirit. The great inflammability of its vapour must be carefully remembered. After successfully completing the operation of ovariotomy, a surgeon covered the wound with a layer of collodion. In order to inspect it more closely he brought a light near, when the ethereal vapour caught fire, and the patient died from the effects of the burns which she received (Binz).

Preparations.

B.P

Collodium Flexile

„ Vesicans.

U.S.P

Collodium cum Cantharide. ,, Flexile. „ Stypticum.

B. and U.S.P. Collodium Flexile. Flexible Collodion. Collodion mixed with Canada balsam and castor oil.

Uses. - Collodion applied to the skin acts both as a protective, and also, through its contraction, exerts a gentle pressure on the part, and is hence applied to cut surfaces, chapped nipples, and to check haemorrhage from leech-bites. The flexible collodion does not crack, and therefore is more useful as a protective, but it exerts less pressure than ordinary collodion.

B.P. Collodium Vesicans. Cantharidal Collodion (blistering liquid 20, pyroxylin 1).

U.S.P. Collodium cum Cantharide. Cantharidal Collodion.

Preparation. - By dissolving a chloroform extract of cantharides in flexible collodion.

Action. - When painted on the skin it acts as a rapid and powerful vesicant. If covered immediately with oiled silk, so as to prevent the evaporation of the ether, it is said to act more rapidly.

Uses. - Vide Cantharides.

U.S.P. Collodium Stypticum. Styptic Collodion.

Preparation. - By dissolving tannin in a mixture of alcohol, ether, and collodion (20 parts tannin in 100).

Uses. - To stop bleeding from leech-bites, abrasions, and wounds. When painted over the bleeding surface the tannin coagulates the blood and lymph; and this, with the collodion, forms a film over the surface which prevents further bleeding and protects the raw surface from exposure to air or from accidental irritation.