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zisrc                                                   549

phate and oxalic acid, but having a strong metallic styptic taste. It is
extremely soluble in water, but insoluble in alcohol. The pharmacopoeial
dose is 10 to 30 grains as an emetic. It occurs in Unguentum zinci oleatis
(Zinc ointment).

3. Zinc Oxide (Jasat bhashm), ZnO.—This is a soft, white, tasteless,
odourless powder, commercially known as Zinc White; it becomes yellow on
heating. The oxide is insoluble in water, but dissolves in acids, forming
the zinc salts. It is largely used as a pigment in place of "white lead",
which becomes blacken&d by hydrogen sulphide present in the atmosphere.

Zinc oxide is a pharmacopoeial preparation and is present in. the official
preparations of Gelatinum zinci (Unna's paste), Pasta zinci oxidi composita
(compound paste of zinc oxide), Suppositoria hamamelidis et zinci oxidi,
Unguentum zmci oxidi and Unguentum zinci oxidi aquosum. Zinc oxide
is also an ingredient of Lotio colammoe. Mixed with zinc chloride in the
form of a paste, zinc oxide is used for filling or stopping carious teeth.

Zinc Phosphide, Zn3Pi>.—This is a steel grey fine powder which is formed
by direct combination of zinc and phosphorus on heating. It is not changed
by air at ordinary temperature, but if triturated in air it gives off the smell
of phosphorus. It is not attacked by water, but cold dilute hydrochloric acid
and nitric acid develop phosphine.

Commercial zinc phosphide is one of the well-known rat poisons. It is
a mixture of different phosphides of zinc in addition to traces of zinc phos-
phate and zinc oxide.

Zinc Stearate.—This is prepared by precipitating a curd soap solution
with zinc sulphate. It is a white, amorphous powder, insoluble in water,
and yields 13 to 15 per cent of zinc oxide. It is used as a dusting powder,
and may produce poisonous effects from its inhalation.

Acute Poisoning.—Symptoms.—A metallic styptic taste, salivation, vomit-
ing, pain in the stomach and abdomen, severe purging, convulsions^ collapse
and death.

Guilbert and Tardieu 27 report the following rare case of perforation of
the stomach resulting from the ingestion' of zinc sulphate : —

A man, aged 53, swallowed 15 grammes of zinc sulphate in mistake for sodium
sulphate, and suffered immediately from severe burning in his mouth, tongue, oesophagus
and stomach followed by salivation, nausea and abdominal pains with vomiting. In an
hour hsematemesis occurred and frequent diarrhceaa with ultimate profuse sweats and
collapse. Twelve hours later, he suffered from painful micturition, polyuria, but no
hsematuria. About two months after the accident he complained of severe pain in the
pyloric and duodenal region on palpation. The X-ray examination revealed perforation
of the stomach which had led to a diverticulum around the pylorus and the duodenum,
and produced chronic duodenitis.\

If zinc chloride is taken, the corrosive symptoms are more prominent
and aggravated. These are burning pain in the mouth, throat, gullet and
stomach immediately after swallowing the poison, profuse salivationr
dysphagia, metallic taste in the mouth, persisting vomiting tinged with blood
and traces of raucous membrane, profuse diarrhoea with blood and tenesmus,
great prostration, collapse and death. In prolonged cases aphonia, perver-
sions of the special senses, tetanic spasms of groups of muscles and muscular
weakness are usually observed. The local action may lead to severe con-
traction of the internal organs with which it comes into contact, and may
cause stricture of the oesophagus or pylorus.

A girl, 2 years old, drank a spoonful (5 grammes) of a 50 per cent solution of zinc
chloride ordered for her mother's endometritis just after, a meal when the stomach was

27.   Rev. de Med., 1932, XLIX, pp. 245-250 ; Hcd.-Leg. and Criminal. Review, April
1933, p. 164.