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.