The sonpensation for occupational hearing loss was established in 1947 by the Lobour Standard Law, and awards have been made by the same criteria as those for acoustic trauma. In 1952, Japanese Shipbuilders Association made some proposals to the Labour Standard Bureau, Ministry of Labour, about the diagnosis of and the compensation for occupational hearing loss, while the ship-building worker's union claimed awards for all cases, where hearing losses exceed 30 db in the speech frequency range, and the Special Committee on Occupational Hearing Loss was organized in 1954 by the Ministry of Lobour to discuss this problem. Such a situation whetted the interest of industrial physicians and research workers in this problem, and the Ministry of Labour began a comprehensive survery on workers exposed to noise in various fields of industry. The compensation problem is still under discussion and the criteria of compensation will be established in near future on the basis of the results of the survey. The present author pointed out some points, which should be taken into consideration in discussing the compensation, such as presbycusis and sociocusis, temporary threshold shift and so on, and he slso introduced some papers on the maximum allowable limit of noise.

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Experimental talcosis, entirely different from silicotic chenges, warw presented by applying absolutely pure talc which had been determined to be free from α-quartz content by qualitative and quantitative an alysis with X-ray siffraction method (Norelco) and phosphoric acid method. 1) Talc, through 200 mesh, was pulverized into less than 5 μ_ο The powder was added to 6 cc Ringer's Solution at 1.0gand sterilized in autoclave. This Preparation (3cc) was injected into trachea of rabbits (containing talc 500 mg). 2) For comparison, another groups of rabbits ware given injection of α-quartz 500 mg respectively. 3) Subjects were histologically checked, grouping into three, after one month, three months and six months. 4)The talc injected subjects unexceptionally produced granulation in alveoli, but marked fibrosis and fusion of nodules were not observed. No swelling was noticed at thorax lymph glands, presenting only image of agglomerated talc particles. 5)With α-quartz injected subjects, fibrosis was extreme. Blood vessels were also affected. Lymph glands ware swollen as big as rice grains at the end of three months, and as beans after six months, demonstrating marked proliferation of connective tissues. 6) It is possible that clinical talcosis is caused by the silicotic chenges to add to that from talc since α-quartz is contained in industrial talc dust.

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Nickelcarbonyl (Ni(CO)₄) is quite a toxic volatile substance and has a special hygienic significance within metalcarbonyls. Its recently revealed utility as a catalyser for the synthesis of acrylic esters makes it more necassary to keep it from accidental exposure. The author intended to make a few studies in Nickelcarbonyl-poisoning for preventive purpose. I a) The Nickel-Value which accrued in the organs of mice exposed to Nickelcarbontl of low concentration was almost proportional to the frequency of exposure and the value is different accordinig to kinds of organs. The amount of Ni in lung (per gram) was the largest and those in liver, kidney, heart were lower respectively and that of brain was the lowest. b) The studies of Rabbits injected with Ni (CO)₄ indicate that the decrease of Bodyweight of experimental animals treated with Ca-EDTA. and Dimercaprol (Bal) was lower compared with that of controls, and the amount of Albumin, Glucose, Urobilinogen and coproporphylin in urine was also smaller than of untreated. The change of blood of control was some-what more evident but not significant. a) The Studies on Ni-Value in organs of experimental animals injected with Ni(CO)₄ indicate that the groups treated with Ca-EDTA. and Bal gave evidently smaller amount of Nickel than those untreated. We can expect some Effect for Ni(CO)₄-poisoning by use of Ca-EDTA. and Bal. II Each mixture of Active Carbon, and Silica Gel was examined to decide the relative capacity of adsorption in to Ni(CO)₄-Vapor, and Thiocarbamide to Nickelcarbonyl. a)The results are that Active Carbon, Silica Gel and each Mixture alike adsord a certain amount of Ni(CO)₄ and at that time it differs from CO. The mechanism of adsorption of Active Carbon and Silica Gel seems to be a physico-chemical process. The amounts of adsorbed-Ni per gram of adsorbents were different and larger in proportion to the degree of thickness of layer, and the capacity of adsorption of Active Carbon was the highest, that of each Mixture was next and that of Silica Gel was the lowest. b) The study on the Gas which had been passed through the layer of Active Carbon (or Silica Gel) and Hopcalite indicates that all mice that were subjected to it entirely survived without any disturbance after 30-minutes-Exposure to the concentration of 14, 000 ppm of Nickelcarbonyl. c) The effect of Hopcalite and Thiocarbamide themselves was none to expect and its experiment proved unsatisfactory.

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A CO₂-O₂ arc-welding process, in which a new gas-shielded metal-arc welding processis, employed, invented by Prof. H. Sekiguchi has come to be applied for practical purposes. Experiments in a small cabin were made to analyse the atomospheric condition by using this welding process. The results of this method were compared with that of the manual welding with covered electrodes. They are summerized as follows. 1) Temperature rising and decrease of humidity were more remarkable in comparison with the welding with covered electrodes. 2) Carbon dioxide increase seen in this method was not so great, though it was much more than on the welding with covered electrodes. This seems to come about by natural ventilation caused by the effect of rising temperature. 3) Carbon monoxide increase was not very much, but it is more than by the other welding process. 4) The production of ultra violet radiation was less than in the case of other welding. 5) The production of ozone and nitrogen dioxide were so slight that they would not cause the poisoning. 6) Quantity of dust produced was consider-ablly large, but less than in the case of the welding with covered electrodes. In using CO₂-O₂ arc-welding process in a small room, one must pay attention to good ventilation of the room, but as this welding process is usually used in a large room with good natural ventilation, there are very few hygienic problems with regard to this welding process.

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The authors have studied on the polarographic wave of serum of silicosis, silicotuber-culosis and tuberculosis. There were found statistically significant difference on the first and second step wave between the above mentioned patients and the healthy, and the former showed a decrease of the wave height in the first reaction and a increase of that in the second reaction compared with the latter. The most marked change was found in the second step wave of the first reaction. Polarographi wave of those who died within 3months after this examination showed a remarkable change of the wave height especially in the second step wave of the second reaction. No significant difference of the wave height in both reaction was found among silicosis, silicotubervulosis and tuberculosis.

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The authors imoroved the ordinary small high barometric pressure for animal experiments to study on the physiological phenomena caused by high barometric pressure and of decompression sickness. As Fig.1 shows, the new apparatus is equipped with an air-compressor (maximum pressure:10kg/cm², air-supply:345 1/min.). It takes 20 minutes to obtain 10kg/cm² pressure. As Fig.2 shows, there are two observation windows on both sides of the tank cylinder. Inside of the tank is well lighted through the upper two windows by means of electric lamps fixed at the top of the cylinder. An electric heater is set up in the tank to warm the room and temperature is adjusted thermostatically. The capacity of the tank is about 1/25 of that of the recompression tank for human, i.e the hospital lock, and it is convenient for animal experiments in respect of getting high barometric pressure rapidly. The tank is also equipped with dozen of leading wire, which connect the inside and outside of the tank electrically, for the purpose of tanking E.C.G, P.C.G., body temperature etc.

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During the finishing processes of cloth-weaving at spinning factories, the workers perform their labour almost always in a standing posture. However, the author's examination of these worker's urine has revealed the absence of any diseased symptoms in it. The author's subsequent examination of the pH, Donaggio-Sato Reaction and Takeya-Kawata Reaction, shown by the urine, has produced the following results. Generally speaking, during the first half of the working hours, the fatigue of the workers gradually increases, while in the second half their fatigue decreases by degrees. At the commencement of their labour, the workers of the later shift show greater fatigue than those of the earlier shift. Probably because the former, before leaving for the factory, are allowed to spend more time at home than the latter. However, as the shift, both earlier and later, go on with their labour, they get more and more accustomed to it, hence less and less fatigue results. To sum up, labour required by the finishing processes of weaving cloth is one below medium degree and the fatigue it causes is one that is completely relieved in the course of the day.

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[in Japanese]

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The following conclusions were obtained as a result of applying Urine Quotient 0/K₃ to 36 subjects exposed to experimental high temperature environments. It was found that the subjects fell under 2 categories. The first group consisted of 14 subjects with low 0/K₃ values which indicated an extremely high resistance to body water loss and inorganic substance, especially sodium loss. This group was designated as a group showing a picture of compliance of the living body under high temperature environments. The second group consisting of 22 showed abnormally high 0/K₃ values, indicating a considerably weaker resistance to body water loss and inorganic substance loss as opposed to the first group. This group was designated as a group showing a picture of non-compliance of the living body to high temperatures.

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Industrial psychiatric studies were performed on the 72 accident proneness workers in a shipyard. Accident frequency distribution of men in each kind of job was first prepared from the accident record obtained during the last 5 years. Then the high accident group (HAG) was selected from the workers in aach distribution above the upper limit of corresponding. Poisson distribution, considering bivariate distribution of the two successive periods during 5 years. Control groups were also selected from the zero or low accident frequency (72 workers) and mode frequency (82 workers) in the same distribution. The Results obtained were as follows: 1. Compared with that of all this shipyard, distribution rate of HAG injuries was somewhat minor in severity. 2. By means of intelligence test and Kraepelin-Uchida character test no significant differences were found between both groups. 3. Individual Rorschach test showed that HAG was inferior in conscious control, emotional stability and maturity, hence in personality adjustment. 4. By aiming test HAG was found less skilful, and "personal tempo" in older age was found slower than that of low accident group (LAG). 5. Psychiatric findings were as follows. In HAG were found 23 mild psychopathics, 5 feeble-mindeds and 7 dull normals. Compared with LAG, significant differences in percentage were shown with regard to mild psychopathic but not to feeble-minded and dull. In psychopathic pattern found in HAG, explosive type (K.Schneider) was the most frequent and the asthenic non-self-confidence type came next. 6. Personality characteristics of HAG as a whole compared with those of LAg were found explosive, weak-willed, careless, oppositional and extroversive. 7. Somatic examination showed no significant differences between both groups. One case of neurotic progressive muscular atrophy was discovered in HAG. 8. HAG's habits of drinking and smoking were somewhat characteristic. 9. The practical rating by foremen showed that HAG had the tendency to insubordination. 10. Turnover rate of HAG was higher than that of LAG. The accident record in the next 5 years proved that most HAG workers had high accident rate. 11. Several case reports were made. 12. Methodology, quality of accident proneness and its relationship to unsafe be-haviour were also discussed.

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The recurrence of pulmonary tuberculosis in persons recovered from the disease and rehabilitated has growingly attracted the attention of health officers in industry. This series of study were undertaken to prevent the recurrence by means of a continuing administration of an antitubercular chemotherapeutic over a long period of time. Sodium isonicotinic acid hydrazide methanesul-fonate (IHMS) was used throughout the study. I. The Influence of Administration of IHMS on the Tuberculin Sensitivity Induced by BCG Vaccination. Sixty-two persons presenting no positive reaction to a tuberculin of usual concentration were divided into 2 groups of same in number. Persons of the one were administered orally an amount of 0.3g of IHMS twice a week for 4 months. At the end of beginning month of administration, all persons of the both group were inoculated with 0.05mg of dried BCG vaccine, they were then tested a tuberculin reaction monthly until the 9th month from the beginning of vaccination. Following results were obtained: 1) The administration of IHMS inhibited definitely the advent of tuberculin sensitivity induced by BCG vaccination. 2) The inhibitory effect of the drug was shown more distinctly in the formation of in-duration than redness of the reaction. 3) The number of tuberculin positive reactors in the each group increased at the period of beginning 1 to 2 months after vaccination, reduced then with the lapse of time thereafter, however, the reduction began much earlier in time and more significant in the group received the drug. II. The Effect of a Continuing Administration of IHMS on the Recurrence of Pulmonary Tuberculosis. One hundred and forty persons who had recovered from pulmonary tuberculosis and are working were subjected to the study. They were divided at random into 2 groups and persons of the one were administered IHMS for 6 and 3 months continuously with an interval of 6 months. The amount of drug and the method of administration were the same as described in the pervious paper. The persons of the other group who did not received the drug were designated as control. All persons of the both group received then roentgenological chest examinations every 3 months for 2 years and the change of their tuberculous foci were followed. The results are as follows: 1) The administration of IHMS reduced the recurrence of disease to one thirds in rate in the group of persons who had shown foci of exudative type at the beginning of experiment, and to one fifths in those of cirrhotic type. In contrast, the improvement of disease rised about 3 times in rate in the persons showing tuberculous foci of the both type initially. 2) No relationship was found between the use of INH in the past and the preventive effect of IHMS on the recurrence of the disease. 3) The reduction of recurrence rate resulted by the administration of IHMS was much greater in the persons of younger age, whereas the rise of improvment rate was more greater in those of older age. III. The Influence of Past History of Pulmonary Tuberculosis on the Chemoprophy-lactic Effect of IHMS. The persons of 140 in number who were subjected to the previous study were investigated their past histories of tuberculosis, namely, the nature of tuberculous foci, the method of treatment for the disease and the time interval from rehabilitation to the beginning of experiment. Then, the relationships between the histories and results of chemoprophylaxis on the recurrence of disease were observed as groups. 1) In the control group, the recurrence rate was higher in persons who belonged to the roentgenological status 1 at the beginning of experiment than those to the status 2, however, the administration of IHNS was equally effective for the persons of both status of disease. 2) The recurrence rate was the highest in persons who had received solely a chemotherapy in the past and the lowest in those who had received both chemotherapy and pneumothorax, however, the reduction of recurrenc

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