The Collodions are solutions in Ether-Alcohol of Pyroxylin or Soluble Gun Cotton. Upon evaporation of the solvent the remaining film excludes the air, thus protecting abraded surfaces. Collodion is also used as a vehicle when a prolonged local effect is desired.

The following forms are official: Per cent

Collodium . . solution in ether 75; alco. 25; pyroxylin

4

Collodium Flexile . . . castor oil 3; Canada turpentine

5

Collodium Stypticum .... alco. 5; ether 25; acid tan.

20

Collodium Cantharidatum (Blistering Collodion) . (flex.

collo.) cantharides

60