USES.--Mixed with one to eight parts of lard it is a blister used to reduce bony enlargements or bone-tumors as in splints, bone spavin, ringbone, sidebone and actinomycosis; it is also used with good results in reducing soft swellings, to arrest chronic inflammation and promote absorption of inflammatory deposits, as seen in sprained tendons, curbs, enlarged joints, bursae, etc. It is frequently used as a counter-irritant in sore throat, chronic cough and roaring. Mixed with cantharides the strength can be reduced as an irritant and less apt to permanently destroy the hair bulbs. It is used internally to arrest the growths of actinomycoses and scirrhous cord, but in those cases the benefits are derived from the potassium iodide which it contains, and I would recommend administering internally without the mercury. HYDRARGYRI OXIDUM FLAVUM--YELLOW MERCURIC OXIDE ORIGIN.--Yellow mercuric oxide is obtained by the interaction of mercuric chloride and sodium hydroxide. PROPERTIES.--Mercuric oxide is of a yellow color, similar to that of the yolk of egg, and is a completely amorphous powder; odorless, and having a somewhat metallic taste; permanent in the air, but turning dark on exposure to light; insoluble in water or alcohol. ACTIONS.--A stimulant caustic and anesthetic. USES.--The official ointment of yellow mercuric oxide is prescribed as a stimulant and anesthetic in chronic inflammation and ulceration of the eye (4 gr. of yellow mercuric oxide to 1 oz. of vaseline). It is also employed on skin diseases, indolent ulcers, swollen glands and granulated wounds. HYDRASTIS--GOLDEN SEAL The rhizome and roots of hydrastis canadensis Linne, yielding not less than 2.5 per cent of hydrastine. HABITAT.--North America in woods west to Missouri and Arkansas. PROPERTIES.--Externally brownish-gray to yellow-brown; fracture short, wood wedges bright yellow, pith large, light yellow, the roots thin, brittle, with a thick yellow bark and a somewhat quadrangular wood; odor distinct; taste bitter. CONSTITUENTS.--Berberine, an alkaloid occurring in yellow crystals; hydrastine, a colorless crystalline alkaloid, soluble in alcohol and ether; canadine occurring in white, acicular crystals. DOSE.--Horses and cattle, 2 dr. to 1 oz.; sheep and pigs, 1 to 2 dr.; dogs, 5 gr. to 1 dr. PREPARATIONS FLUIDEXTRACTUM HYDRASTIS--FLUIDEXTRACT OF HYDRASTIS Made by maceration and percolation with alcohol, glycerin and water and evaporation. DOSE.--Horses and cattle, 3 drs. to 1 oz.; sheep and pigs, 1 to 2 drs.; dogs, 5 gr. to 1 dr. TINCTURA HYDRASTIS--TINCTURE OF HYDRASTIS Made by maceration and percolation of hydrastis, with diluted alcohol. DOSE.--Horses and cattle, 1 to 2 oz.; sheep and pigs, 2 to 4 drs.; dogs, ¹⁄₂ to 2 drs. GLYCERITUM HYDRASTIS--GLYCERITE OF HYDRASTIS