Charcoal is used in surgery to cleanse and alter the condition of old and sloughing ulcers, suppurating sores and wounds, and is sometimes applied directly to them in the form of powder, or poultice with bread; to relieve offensive odors it is better enclosed dry in muslin bags and placed near the wounds. In open cancer a paste of soot with glycerin is said to be a useful application (Debreyne: Medical Times, i., 1860, p. 402). For offensive perspiration of the feet or axillae, charcoal may be mixed with alum or zinc oxide, and used as a dusting powder; with chalk it forms a cleansing dentifrice.