Cocaine is the alkaloid of the coca leaves. It is obtained by digesting or macerating the leaves with water or alcohol, precipitating, purifying and crystallizing the alkaloid. Pure cocaine forms colorless crystals without smell, of a bitterish taste; soluble in 704 parts of water, more soluble in alcohol, best in ether. The solutions taste bitter. Chloride or acetate of cocaine are the commercial preparations, white crystalline powders, in water and alcohol easily soluble. It is proposed to make a small addition of a preservative (salicylic acid) to its solution, in order to prevent fungoid growth; however, we found none of the latter in our solutions, and consequently did not make use of preservatives. Besides cocaine, a volatile alkaloid has been obtained by some chemists and termed hygrine, which remains a liquid.