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CHROMIUM                                                            559

and, therefore, exists in " battery fluids" used in bichromate cells.    It is  a powerful
corrosive, and is used as a caustic in medicine.

Potassium Chromate, K2CrO4.—This is a yellow, crystalline salt with a disagreeable
bitter taste, and readily soluble in water, the solution being alkaline in reaction. It is
chiefly used in manufacturing chrome yellow (lead chromate), a very poisonous salt.

Potassium Dichromate (Eed Chromate), K2Cr207.—This is also known as potassium
bichromate. It is an orange-red, crystalline salt, having a bitter and metallic taste. It is
soluble in ten parts of water, forming an acid solution, which is highly poisonous, having
a special action on the nervous system. It is insoluble in alcohol. It is used by dyers,
furniture stainers and photographers.

Acute Poisoning.—Toxic effects appear within a few minutes, say 5 minutes or less,
after swallowing the poison, usually potassium dichromate or chromic acid. The
symptoms are bitter metallic taste, intense pain in the stomach, vomiting and diarrhoea.
The vomited matter is yellow, and sometimes tinged with bile and blood. The stools
are yellow owing to the reduction of the salt, and may contain blood. The urine is
suppressed or is passed in small quantity and contains blood and aLbumin. The pupils
are dilated, and do not react to light. The respirations are very slow and gasping. The
pulse is feeble and almost imperceptible. These are followed by muscular cramps, col-
lapse, unconsciousness and death. Convulsions may occur in some cases.

Fatal Dose and Fatal Period.—A tablespoonful of a 50 per cent solution of chromic
acid has caused death. A tablespoonful of potassium chromate has proved fatal in 12
hours. The smallest fatal dose of potassium bichromate is 30 to 45 grains. Two drachms
of potassium bichromate have caused death in 4 hours, but recovery has followed a dose
of half an ounce. A woman,5? aged 21 years, died on the tenth day after swallowing
15 grammes of potassium bichromate with intent to commit suicide.

Treatment.—Empty the stomach by emetics, or wash it out with warm water. Give
solutions of magnesium or calcium carbonate in water or in milk, and administer demul-
cents as well as stimulants.

Post-mortem Appearances.—The mucous membrane of the stomach is inflamed and
corroded in patches, and coloured olive-green or purple due to the conversion of the
salt into an oxide. The duodenum also shows the same appearances. The blood is
chocolate-coloured and shows the spectrum of methaemoglobin. Fatty degeneration of
the liver and heart, and acute inflammation of the kidneys. In the case of death from
potassium bichromate reported by Dr. Willcox there were no changes in the viscera
except slight brown discoloration of the stomach wall. The chemical analysis revealed
the presence of chromium in the viscera.58

Chronic Poisoning.—This is apt to occur among those who are employed in the
manufacture of chromic acid and its salts, and are thus constantly handling them, or are
exposed to their dust.

Symptoms.—Bitter, nauseous taste in the mouth, irritation and inflammation of the
mucous membrane of the nose causing sneezing, salivation, lachrymation, severe conjunc-
tivitis, laryngitis and bronchitis. The nasal membrane then becomes ulcerated, and per-
foration occurs in the lower part of the septum.

Ulcerated sores, known as chrome holes, occur on the hands, face and other parts
of the body. These are not very painful and rarely suppurate, but they penetrate deeply
and are obstinate in healing. Eczematous and psoriatic rashes may also appear on the
skin, and the periosteum may be inflamed and painful.

Treatment.—Ulcerated sores should be scrubbed with 5 per cent sodium thiosulphate
solution, and should then be treated like ordinary wounds. The workers should protect
their hands and feet by wealing rubber gloves and boots and should wear gas masks
to prevent the inhalation of chrome dust and fumes. They should also observe thorough
cleanliness and wash their hands with soap and water before taking meals. Oil should
be sprayed on the nasal septum before going to the factory. Lastly adequate exhaust
ventilation should be provided for removal of dust and fumes from the atmosphere.

Chemical Tests.—An alkaline solution of a chromium salt yields a green precipitate,
soluble in excess on the addition of ammonium sulphide. With a solution of nitrate or
acetate of lead, chromates or bichromates give a bright yellow precipitate, soluble in
boiling water. This solution on cooling, deposits golden yellow spangles of lead chro-
mate. Chromates give a violet colour to diphenyl carbazide dissolved in 1 part of acetic
acid and 9 parts of alcohol. A solution of chromic acid gives a yellow precipitate with
barium nitrate or chloride, soluble in hydrochloric and nitric acids. With silver nitrate
it gives a brick-red precipitate, soluble in ammonia. When boiled with dilute sulphuric
acid and alcohol or formalin, it acquires a green colouration.                            *

57.    Leschke, Clin. Tox., Eng. Transl. by Stewart and Dorrer, 1934, p. 85.

58.    Trans. Med.-Leg. Society, 1909-10, p. 69.