The author reported the outline of occupational health services to employees of small plants in U.S.A and in Europe, which he had recently inspected, at the 2nd general meeting of the Society for the Study of Occupational Health Problems of Small Plants in Osaka 1964. In both Europe and U.S.A., the health and medical services are lacking in small plants in general. Pilot experiments or programs of providing health and medical service to employees in small plants have been attempted in U.S.A. and in England. The patterns of the program are different according to the socio-economical and political conditions as well as the health and medical service system as of the state or the community. 1) Individual Program: It is the basic needs for the health service to employees in small as well as large plants to provide an individual health unit, e.g. medical equipment and medical personnael, in the plant. Otherwise, this program has frequently been miscarried mainly due to economical reason of the medical personnel. 2) Cooperative Program : The provision of a cooperative medical equipment or "Industrial Health Center" to a group of small plants is more favourable and effective to get the medical personnel and the well-equiped facilities. Slough Industrial Health Center and Harlow I.H.C. in England are worthy to be praised as well-arranged models of the cooperative health and medical service to small plants, which includes Central Clinic, mobile redressing service, health examination, inspection and research of work place, etc. These pilot experiments have shown that the assistance and the sponsor of the state, the community or the voluntary agencies should be the prerequisite to success of these programs, especially by means of a high initial investment. 3) Community Program: It is more effective and necessary to draw out the resources available in the community; hospitals, general physicians, nurses, institutes, volunteary agencies, especially official agencies. For instance, the cooperative activities of Bureau of Industrial Hygiene and the public health nurses of the health centers of Detroit Department of the Health are showing effective guidance and recommendations to improve the health services to employees in small plants. Besides, the part-time sevice of localgeneral physicians and their medical treatment in the offices should constitute the "backbone" of the health service to employees in small plants. On the other hand, criticisms to these programs, especially to so-called cooperative program for small plants, should not be overlooked, that is, these programs consist mainly of personal, rather clinical, medical services. For the health of employees the improvement of the unhealthy working conditions and the amelioration of the unhygienic environment in small plants should be the most essential needs, and the official inspection of factories and the recommendations to keep the legal hygienic standard should also not be neglected. Besides, the authour added a short description of the industrial health services in Czechoslovak, which have a tight correlation with the national socialized heath and medical service scheme, and of the initiative of Labour Union on Safety and Health in work places in the Socialist Republic.

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The experiment on the acute oral toxicity of some organic mercury compounds that were available was made to evaluate LD₅₀ of each compound. The result was as follows: 1) Acute oral toxicity of several organic mercuric compounds used for pesticide was tested on rats. The oral LD₅₀ was strongest for methoxyethylen mercuric chloride, being 26.2 mg/kg, next comes phenyl-mercuric acetate with LD₅₀ of 39.5 and then ethylmercuric phosphate (50.8), ethymercuric choride (60), and phenylmercuricp-toluene sulfonic acid (88.9) in the decreasing order. 2) As for the symptoms in the acute poisoning, depression and diarrhea were eminent. Some cases showed bleedings in the peri-oral area. Rats died in prostration, without any sign of tremor or paralysis. 3) Histopathological findings of the kidney were characterized by severe congestion accompanied with nephrosis while in the liver acute inflammatory changes with congestion and fatty degeneration were found. There was found no difference regarding the chemical structures of organic mercuric compounds tested in this experiment.

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It has been an usual approach for the study of organic mercury metabolism to analyze the total mercury in tissues and excreta as a whole, owing to the difficulties in differentiating organic mercury from inorganic one. The Miller's method for the determination of phenylmercuric compounds, i.e. the extration by an organic solvent under very low pH following the mild alkaline digestion of organic matters, was found also to be appliable to ethylmercuric compounds by Nishimura and the author. Based on this fact, the short-term metabolism of ethylmercuric phosphate in rabbits and chronic intoxication in rats were investigated. When phenylmercuric phosphate was injected intramuscularly to rabbits, the peak in urinary excretion came on the second day and it decreased grandually until the sixth day, when no more organic mercury was detected in the urine. The rats were given water containing 5 ppm of ethylmercuric phosphate ad libitum for150 days, thereafter it was increased to 50 ppm for 23 days to induce poisoning symptoms in a shorter period. For the comparison, the inorganic mercury (mercury nitrate) was given to the positive control group in parallel. The animals were sacrificed at the end of the experiment and fractional determinations of mercury in the brain, liver and kindney were conducted. It was clearly demonstrated that the organs contained mercury in high concentration, of which the major portion was of organic nature. Hence the total mercury content in the organs amounted to three to seven times as high as that in the inorganic mercury group. However, even in the organic mercury group, some "apparent inorganic" mercury (inextractable mercury) was always found in organs over the usual range. It was uncertain for the present, whether it had come from the degredation of organic compounds to inorganic ones in the body or merely the fixation of organic mercury to some proteins occurred which was very resistant to the mild alkaline digestion and extraction procedures.

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