Characters. - A soft, nearly white, tasteless and inodorous powder, becoming pale-yellow when heated.

Impurities. - Undecomposed carbonate, chloride, sulphates, iron and copper.

Tests. - Dissolves without effervescence in diluted nitric acid, forming a solution, which is not affected by chloride of barium or nitrate of silver, and gives with carbonate of ammonium a white precipitate which dissolves entirely (no iron) without colour (no copper) in an excess of the reagent, forming a solution which is precipitated white by sulphide of ammonium.

Dose. - 2 to 10 grains.

Officinal Preparations.

B.P. Unguentum Zinci.

B.P. Unguentum Zinci.

lard 1 oz., or 1 in 6 1/2 nearly.

U.S.P. Unguentum Oxidi Zinci. 20, benzoated lard 80, or 1 in 5.

U.S.P

Unguentum Oxidi Zinci. Zinc Ointment. - Oxide of zinc 80 grs., benzoated

Ointment of Oxide of Zinc. - Oxide of zinc

Uses. - Oxide of zinc is sparingly soluble in the stomach. It dissolves to a slight extent, too little to act as an emetic, but sufficient to produce the action of small doses of soluble zinc salts as a nervine tonic and astringent.

It may be used as a dusting powder in intertrigo, and the zinc ointment is one of the most efficacious remedies we possess for application to excoriated surfaces. In acute eczema, zinc ointment can sometimes be borne, when other forms of bland ointment only increase the inflammation, and in acute vesicular eczema, dabbing the part for about fifteen minutes with black wash and then rubbing in zinc ointment gently is sometimes a very successful treatment. It has been given in whooping-cough, epilepsy, hysteria, nervous headache, and to check profuse sweating in phthisis, and profuse secretion from the bronchi in bronchitis. In the sweating of phthisis it is frequently combined with hyoscyamus, and it is somewhat difficult to say how much of the beneficial action is due to the hyoscyamus.

B.P. Oleatum Zinci. Oleate of Zinc (p. 591).

B.P. Officinal Preparation. Unguentum Zinci Oleati (oleate of zinc 2, benzoated lard 11).

Uses. - Ointment of oleate of zinc alone, or along with oleate of morphine, is an excellent preparation in many cases of acute eczema and of intertrigo.