Health examinations on 38, 477 workers working in 519 small plants and thier 9, 928 family members in western Japan were intended during 8 months from April to November 1959, but 22.8% of the former and 51.9% of the latter failed to undergo the examination. Rate of this failure was higher in the districts where especially small industries gathered, while it was low in those where many larger industries having their own health insurance schemes were situate. 964 workers corresponding to 3.2% of the examinees were found to have further minute examinations necessary. Out of these only 668 (69.3%) actually underwent that examination by which 14.4%, 34.4%, 14.9%, 30.0% and 6.3% were classed as A, B, C, D, and "no findings" respectively, according to the seriousness of the disease. Family members who underwent the mass examination were 4769, of which 234 were examined minutely with the result that 12, 44, 58, and 37 were classed as A, B, C, and D respectively. To 103 out of 215 who necessitated medical supersvision isoniazid glucuronate were given daily by an amount from 0.6 to 1.0 gram for twelve months, and examinations were done with an interval of three months. Through X-ray examinations, 17 cases of improvement (16.5%), 83 stationary cases (80.6%), 3 cases of aggravation (2.9%) were found. As to the sedimentation rate of red blood corpuscles and the change of body weight nothing notable was found. Light nausea was the main side effect.

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Workers exposed to dusts of antimony oxide or sulfide in the refining process of N mining company were examined clinically and the tissue reactions experimentally produced by antimony dusts were studied. 1. Clinical studies of the workers revealed that many of them showed an inflamation of the upper respiratory tract, gastrointestinal disturbances, and dermatitis. Eighty percent of them showed a slight pneumoconiosis by Xray examination. Concentrations of antimony dusts in the air were 0.7 to 8.9 mg/m³. 2. Antimony oxide dusts produced a cellular granuloma in the lung or peritoneum of rats when inttroduced intratracheally or intraperitoneally. In the lymph gland of these treated animals, granulomas characterized by the proliferation of reticulum cells and the cells similar to plasma cells were found, while the proliferation of collagen fibers was not dedectable.

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(I) Comparative Studies on the Fatal Dose of Nitrolime for Various Species of Animals Although many studies have been performed on the dose of poisoning especially on the fatal does of nitrolime, a considerable difference is observed by the species of animals and by the ways of its administration. The following experiments were performed for the purpose of determining the fatal dose of nitrolime in various ways of administration and in various species of animals, such as rats, mice, dogs. The results were as follows: 1. The fatal dose for rats by subctaneous injection was 0.4∼9.7 g/kg, LD₅₀ was 0.45 g/kg, and the toxic dose was 0.1 g/kg. 2. The fatal dose for rats by oral administration was 0.5∼1.1 g/kg, LD50₅₀ was 0.7 g/kg. 3. When 2cc of 15% alcohol was given orally in addition to the subctaneous injection of nitrolime solution, the fatal dose for rats was 0.2-0.7 g/kg, LD₅₀ was 0.3 g/kg. 4. The fatal dose for mice by subctaneous injection was 0.4∼1.1 g/kg, LD₅₀ was 0.68 g/kg. 5. The fatal dose for dogs by subctaneous injection was 0.5 g/kg. After examining the above mentioned results, the fatal dose in man with the body weight of 50 kg can be presumed to be 5∼12.5 g (around 10 g) by subctaneous injection and 5∼19 g (around 13 g) by oral administration. (II) A New Dust Inhalation Apparatus and its Application to the Experiment of Nitrolime Inhalation in Rats For the purpose of determining the critical dose of nitrolime that induces poisoning in rats, the author designed a new dust inhalation apparatus. By the use of the apparatus nitrolime dust was introduced into 114 rats. The results were as follows: The fatal dose in rats was 60∼110 mg/kg, LD₅₀ was 120 mg/kg, and the toxic dose was 30 mg/kg. It is presumed that the fatal dose by inhalation in a human adult is 1.0∼2.5 g, the toxic dose is 0.5 g, and the maximum allowable concentration is 150 mg/m³. (III) Effects of SH-Substances on Nitrolime Poisoning The effects of six drugs with sulfhydryl radical were compared in poisonings in rats and mice by nitrolime. The following results were obtained. "Hypon" and "BAL" were not so effective, glutathione and cystein were moderately effective, and "Paniltin" and methionine were the most effective against nitrolime poisoning.

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