The proper salts of mercury are at present scarcely used except for topical purposes. The nitrate and acetate were at one time given internally, but have been generally abandoned. Of the salts in use, I shall treat in this place only of the nitrate, in the form of the citrine ointment. The yellow subsulphate or turpeth mineral will be considered with the emetics and errhines, and the solution of the pernitrate or supernitrate with the escharotics.