The main interest in the vibration study is concentrated upon the definition of the allowable limit for worker's health supervision. This study deals with the relation between vibration sensitivity and velocity, acceleration and jerk, and also with a scale of sensitivity of vibration. This will contribute to clarify the allowable limit. Although the relations between vibration sensitivity and velocity, acceleration and jerk are related closely in a specified frequency range, there is lack of uniformity in the results obtained by different researchers in this problem. For the advancement of the study, it is desirable to set up an international unit for the estimation of the intensity or magnitude of vibration. To develop and utilize more widely the unit "trem" is promising also for the synthetic estimation of vibtation and noise in the future study. It is also desired to prepare a vibration meter which corresponds to human sensitivity for vibration. Many studies on the allowable limit for the whole body's vibration have been reported, but their values are remarkably different by the reasons of the different experimental conditions or different subjects to be applied. In the present study the allowable limit of vibration is presented with mean and standard deviation accrding to the date of Janeway, Goldman, Helberg, WADC, RAF, VDI and Volkov (U.S.S.R.). (The date also includes the results of Reiher, Meister, Jacklin and Liddell.) The limit curve is 0.060±0.030 G under the condition of 6 c/s as shouwn in Fig.7. Accoding to respective cases, man can abopt the upper or limit of this curve. In addition, the data of Ziegenruecker, Magid, Coermann, Mandel, and Lowry have been examined and represented with mean and standard deviation as the hazardous limit.

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Some facts related to menarche and menstrual disorder were reported in the previous report. This study was undertaken to clarify the factors affecting to take menstruation leave. Three hundred sixty-nine female workers in a chemical industry were observed from April, 1962 to December, 1963. And a comparison was made between female and male workers in the same workshop, regarding the rate of absence for reasons. Until March, 1963, the female workers were paid no wages for days of absence owing to menstruation; but, after April, 1963, wages during the menstruation leave became paid to them. By this change of terms of payment, the absence because of menstruation increased after April, 1963. Hence, a comparison in the rate of absence because of menstruation was made numerically between the period before March and that after April, 1963. The results were as follows. Before March, the monthly and weekly variation of the rate of absence because of menstruation could not be seen. But, after April, the rate decreased in the period 5th to 7th and 25th to 27th of a month. The rate of absence for reasons other than menstruation (i.e. private reasons, illness) also decreased in the same periods of a month among both females and males. The decrease at the end of a month is explained by the fact wages are paid in the period 25th to 27th of a month. The rate of absence was higher in the middle than at the end and beginning of a week. This fact may be considered as due to the influence of the information, that the absence because of menstruation including the off-day in undesirable, by the labor union of this workshop.

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1. 3-amino-1, 2, 4-triazole (triazole) injected to Donryu rats in a dose of 0.001g/kg intraperitoneally supressed phenol production in the liver homogenate during the first to the twenty fourth hour after the injection (Tab. 2) . Simultaneous administration of triazole decreased the urinary excrerion of phenol by the oxidation of benzene (Fig. 4). 2. Although triazole was ineffective to hemopoiesis of rats (Tab. 3) and benzene caused the hemopoietic disturbance in rats (Tab. 4), triazole lightened myelotoxic action of benzene when it was injected in parallel with benzene (tab. 5). 3. From the above results, it is thought that triazole desturbs the oxidation of benzene and it acts to produce so small amount of phenol that myelotoxic action of benzene appears to be suppressed. In other words, myelotoxicity of benzene may be resulted not from benzene, but from the metabolic changes of benzene.

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The static conditions of peripheral vascular systems were observed on the workers in hot environments and dynamic changes to cold and hot stimuli were also examined.Six men 22 to 27 years old engaged in hot environments for about three years were originally selected for this study, and simultaneously six clerks of the same ages were examined as a control group. They were measured before and after working in summer and winter respectively on the changes of capillary figures and pulse waves in the left fingertip skin at the room temperature, than on the changes to cold and hot stimuli (7±2°C, 49±2°C) for every ten seconds applied on the back of the same hand. The results obtained were as follows: 1) The effects of working in hot environments were not found in the width of skin capillary figures, but a tendency toward lowering after working was seen in the visible height of capillaries, especially in summer. 2) Ordinary redustions in the amplitude of pulse waves were observed after working in both seasons, but these changes were not shown as characterisitic of the hot environmental group. It is considered that the tension of peripheral blood vessels may be changed by working. 3) The chnges to cold stimuli before working were observed to be more insensitive (prolongation of the reaction time) in summer, more sensitive in winter in the hot environmental group, than that of the control group, and no significant changes were found between the both groups after working. The changes to hot stimuli before working were also observed to be more sensitive in the hot envitonmental group than that of the control group, especially in summer, but no significant difference after working was shown between the both groups. In winter, a tendency of sensitive reaction was seen in the hot environmental group after working compared with the control group, in spite of no significant difference was recognized in both groups before working. The workers engaged in hot environments are relatively stable for cold stimuli and labile for hot stimuli after working and it suggests that the acclimatized workers have been prepared to escape the heat stress in the body. 4) As a rule, the crest time shortens in winter compared with summer. The ratio of the time necessary for constriction of blood vessels to the duration of pulse waves (t/d) was lower in the hot environmental group than the control group before working, especially in summmer, but this difference was not significant between the both groups after working.

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