(1) By the mouth. - The Liquor Hydrargyri Perchloridi B. P. which is corrosive mercuric chloride, 1; ammonium chloride, 1; water, 1000 is often given to adults, usually in doses of I to 2 fl. dr. 4. to 8. c.c. For the later symptoms of syphilis, potassium iodide is often combined with it. Mercuric iodide is formed and is kept in solution by the excess of potassium iodide. Mercurous iodide, known as the yellow iodide, is much used by some. It is insoluble in water, and is incompatible with potassium iodide, red mercuric iodide and metallic mercury being formed. The best preparation for children is 1/2 to 1 gr. .03 to .06 gm. of gray powder, given just often enough to avoid purgation.

(2) By The Rectum

Occasionally mercury is given as a suppository. Each may contain 5 gr.; .30 gm. of mercurial ointment.

(3) Endermically

Mercurials, especially calomel, are often dusted on sores and ulcers, and lotions are also locally applied. Mercury can be absorbed in this way.

(4) By Inunction

Blue ointment may be rubbed into the skin. The best position is the inner side of the thigh. Usually a piece the size of the top of the thumb, rubbed in once a day, is enough. It has been put inside the sock, for then it is rubbed into the foot during walking. A very efficient way of applying the ointment in children is to smear it on a flannel binder which is worn round the abdomen. The oleate may be employed for inunction; this possesses the advantage of not staining the clothing. Mercury is rapidly absorbed by these means.

(5) Hypodermatically

One-eighth of a grain .008 gm. or less of the Corrosive Chloride dissolved in about 5 to 8 minims .30 to .50 c.c. of distilled water is used for a dose. The needle of a hypodermatic syringe is plunged deeply into some muscles, preferably those of the gluteal region, and to the outer side of it, so that the patient does not sit or lie on the spot. If much pain is caused, a piece of ice may be held over the part before the injection and after the needle is withdrawn. The injection should be repeated daily; before going to bed is a good time. With proper care no abscesses result. This is a very rapid and thorough way of bringing the patient under the influence of mercury. Mercuric cyanide is also a good salt for subcutaneous injection.

(6) Fumigation

Calomel, the black oxide, or the red mercuric sulphide known as Cinnabar (neither of the last two are official), may be used. The patient, who is naked, sits on a cane-bottomed chair; a blanket, which reaches to the floor, is fastened lightly round his neck. Twenty grains 1.20 gm. of the salt are placed in a porcelain dish, over a spirit lamp, under the chair. The mercury volatilizes, and is absorbed by the skin. A bath should last twenty minutes; with obvious modifications this method may be applied to patients in bed.

(7) Inhalation

This is rarely or never used.

(8) Baths of three drachms 12. gm. of corrosive chloride to thirty gallons 114 liters of water, with one fluid drachm 4. c.c. of hydrochloric acid added, have been used, but they are now very rarely employed.