USES.--For internal use milder preparations of mercury are preferred, and it is dangerous to use it for the production of mercurialism. For horses it has been prescribed in tetanus, chronic skin eruptions and swollen oedematous legs following repeated attacks of lymphangitis. Its chief use is that of an antiseptic externally for many surgical purposes, usually in the strength of one to five hundred, one to one thousand; for uterine injections, one to five thousand or one in ten thousand. Seven and a half grains to a pint of water makes a one to one thousand solution. Seven and a half grains to a quart of water makes a one to two thousand solution. Fifteen grains to a pint of water makes a one to five hundred solution. Instruments, sponges, towels as well as the hands are disinfected by washing in a one thousandth solution. But it is injurious to most metal instruments and irritates and roughens the operator’s hands. Best antiseptic for foul wounds, thrush, poll-evil, quittor and fistulous withers and nail punctures of the feet, a one in five hundred to one in one thousand solution to destroy the cryptogamic growths of ringworm, to kill lice and allay the itching of puritis and urticaria. Bichloride of mercury one part in one or two thousand parts of water is injected into the uterus in metritis, and in cases of abortion with good results. Contagious abortion is satisfactorily prevented by washing the aborted animal’s tail and external genital organs twice daily. All pregnant cows should be treated in the same manner. Warm solutions are much more active than cold. A one in three to five thousand solutions are used in purulent conjunctivitis or wounds of the eye and lids, by frequently saturating absorbent cotton in the solution and holding over the eye by means of a clean cloth or bandage. DOSES.--Horse, 1 to 5 gr.; cattle, 2 to 8 gr.; sheep, ¹⁄₂ to 1 gr.; pigs ¹⁄₈ to ¹⁄₂ gr.; dogs, ¹⁄₆₀ to ¹⁄₁₀ gr. Not often given internally. It is the best of all the preparations of mercury for hypodermic use in syphilitic diseases. ANTIDOTES.--The white of eggs, stomach pump for horses and emesis for dogs; wheat flower, milk, etc. HYDRARGYRI CHLORIDUM MITE--MILD MERCUROUS CHLORIDE--CALOMEL ORIGIN.--Calomel is obtained by heating a mixture of mercurous sulphate and sodium chlorid. Calomel is found native in Spain and Carniola, but in too small quantities for commercial value. PROPERTIES.--Calomel is a dull-white heavy powder. It is inodorous, insoluble in water, alcohol or ether.