A Collodion is a solution of pyroxylin (gun-cotton) in a mixture of ether and alcohol. It is a highly inflammable liquid. When applied to a surface, the solvent evaporates, leaving deposited a transparent, tenacious film.

Prepare the official Collodium as follows: In a bottle place 2 Gm. pyroxylin, add 12.5 mils alcohol; thoroughly shake the mixture; then add 37.5 mils ether, and shake this mixture until the pyroxylin is dissolved. Cork the bottle tightly, setting it aside until the liquid has cleared; then decant the clear portion, place in a suitable bottle, and cork tightly.

All these operations must be conducted away from the vicinity of any flame.

Prepare the official Collodium Flexile as follows: Tare a small bottle, and into it place 19 Gm. Collodion, 0.4 Gm. camphor, and 0.6 Gm. castor oil; shake the mixture until the camphor is dissolved.

This preparation should be kept in well-stoppered bottles, in a cool place, and well removed from the fire.

Properties of Collodia,............................................................................................................................................................................

Paint one knuckle with Collodion, and an adjacent knuckle with Flexible Collodion. On flexor surface of forearm, paint comparative areas with the two in the same way.

Collodium:

Collodium Flexile:

Sample......................................................................................................

Sample.....................................................................................................

Appearance ..........................................................................................

Appearance ..........................................................................................

Color .........................................................................................................

Color .........................................................................................................

Odor............................................................................................................

Odor............................................................................................................

Flexibility ...........................................................................................

Flexibility ..........................................................

Adhesiveness ....................................................

Adhesiveness ....................................................................................

Contraction ..........................................................................................

Contraction .........................................................................................

Collodia are used as adhesive protectives; also to render cotton dressings more concrete and impervious. They are being in part supplanted by the new flexible paraffin dressings.

There is one other official Collodion: Collodium Cantharidatum. This is an obsolescent preparation, well deserving complete discard.