NICKEL AND COBALT 569 intensely congested, and the heart was in a state of degeneration and loaded with fat. The other organs including the brain were congested. Dr. Mott further examined the brain of one of the deceased and found capillary haemorrhages in its substance and chromolytic changes in the nerve cells of the medulla and pons, especially of the cardio- respiratory centres.02 Workmen employed in the cobalt mines of Schneeberg and Joachimsthal often suffer from malignant lymphosarcoma of the lungs, known as the Sdineeberg lung cancer. This condition is probably due to the inhalation of the dust of arsenic and radium present in cobalt ores. A case of acute poisoning has, however, occurred from the inhalation of cobalt dust free from arsenic. A young man who was working at the breaking of cobalt in a narrow, unventilated room was "taken ill with stomach pains, eructation and very violent vomiting. He suffered from hasmaturia which lasted for three months.93 Symptoms.—Nausea, vomiting, headache, giddiness, fever, dyspepsia, convulsions, coma and death. Post-mortem Appearances.—The stomach and intestines are ecchymosed and inflamed. The brain is congested. The lungs are congested and cedematous. The heart is flabby and dilated. When cobalt is taken internally it is eliminated by the faeces, and when administered intravenously, it is excreted in the urine. Chemical Tests.—1. Ammonium chloride, ammonium hydrate and ammonium sul- phide yield a black precipitate with nickel and cobalt salts. 2. Caustic potash, caustic soda or ammonium hydroxide gives a green precipitate with a nickel salt, and a blue precipitate with a cobalt salt, soluble in excess, 3. Cobalt gives a blue borax bead and nickel, a reddish-yellow or grey bead. 4. An alcoholic solution of dimethylglioxime gives a scarlet precipitate with a solu- tion containing a nickel salt and ammonia or ammonium, acetate. OSMIUM Osmium Tetroxide (Osmic Acid), OsO4.—This is a crystalline salt, melting at 40°C. and boiling at 100 °C. It has a caustic, burning taste and a penetrating odour. Its vapours are most irritating and poisonous, the chief injurious effects being inflammation of the eyes and respiratory passages, and painful eruptions on the skin. RADIO-ACTIVE SUBSTANCES Thorium, uranium and radium and their salts are known as radioactive substances as they are constantly disintegrating spontaneously and emitting radiations, which are capable of affecting a photographic plate through a black paper, and also of discharging an electroscope. When inhaled, ingested or handled, these radioactive substances produce poisonous symptoms especially in industrial processes. Symptoms.—These are weakness, emaciation, progressive aplastic anaemia, necrosis of the mandible and other bones, malignant" growth of bone and carcinoma of the lungs. In some cases general sepsis may result from secondary infection. The breath may show radioactivity. Treatment.—Treat anaemia and other complaints. Blood transfusion may be tried. Parathyroid extract and a low calcium diet are recommended, to increase the rate of excretion of the radioactive material from the body. As a prophylactic measure rigid personal hygiene must be enforced among workers who are exposed to the radioactive substances. A high calcium diet must be given to workers to prevent the absorption of the radioactive material into the system. Post-mortem Appearances.—All the soft tissues, organs and the bones of the body show the presence of the radioactive material. Medico-Legal Points.—Poisoning generally occurs among workers employed in the extraction of radioactive substances from the ores. It has occurred among young women from the slow ingestion of a self-luminous paint, which was applied to the figures on the dials of watches and clocks with camel's hair brushes, which they habitually brought to a point with their lips and tongue.94 The self-luminous paint consists of a radioactive substance and zinc sulphide. Poisoning followed by death has also occurred in a man, 52 years old, who drank tonic water containing a radioactive substance for about five years.95 92. Brit. Med. Jour., Jan. 24, 1903, p. 214, and Feb. 21, 1903, p. 416. 93. Remond and Favre quoted by Leschke, Clin, Toxic., Eng, Transl. by Stewart and Dorrer, 1934, p. 87. 94. Martland, Jour. Amer. Med. Assoc., LXXXV, 1925, p. 1769. 95. Gettler and Morris, Jour. Amer. Med. Assoc., Feb. 11, 1933, p. 400.