Plasters are solid, adhesive preparations, spread on some fabric, and usually requiring warming before being applied to the body.

Prepare as follows a satisfactory substitute for the official Emplastrum Sinapis: To 8 Gm. flour add 4 Gm. mustard; mix thoroughly, then add just enough warm water (not hot) to make a soft smooth paste. Spread this on heavy paper or on cottoncloth.

Bind some of your prepared Mustard Plaster on the flexor surface of your forearm, and leave it there until distinctly sharp sensations are perceived. Remove plaster, and examine appearance of the skin. Report:....................................................................................................................

Time taken for effect:.......................................................................................................................................................

Nature of effect:...................................................................................................................................................................................

Duration of effect:.......................................................................................................................................................................................

The following Plasters are official: