In Japan, by all possible preventive steps, serious cases of paroxysms of angina pectoris due to nitroglycol poisoning has been almost disappeared. Therefore, it is difficult to draw an exact line whether many subjective symptoms and clinical abnormal findings, which have been thought to be not so characteristic at nitroglycol exposure, are connected with nitroglycol or not. To ascertain the actual conditions in a dynamite factory and the adrenocortical reserve functions of workers exposed to nitroglycol, some investigations were attempted. Results are as follows; 1) In the dynamite factory, concentration of nitroglycol in an extruding room has been notably decreased year after year, and at present it is less than 0.2 ppm, i.e. the MAC value in Japan. 2) Concentrations of NO₃ content in the blood of dynamite workers do not increase so apparently after work. 3) Subjective symptoms of dynamite workers, except for headache, are statistically not significant in comparison with those of other workers. 4) Clinical abnormal findings of dynamite workers are not significant in our investigated items compared with other workers. 5) Adrenocortical reserve functions in dynamite workers, which were examined by a reaction to ACTH injection, were apparently decreased. Changes in eosinophil counts on dynamite workers were notably different from those of office workers; namely, in cases where no drug had been injected, eosinophils increased in about a half of the workers after four hours work. 6) But, there are no relation between adrenocortical reserve functions and other subjective symptoms or clinical findings. From these facts, the conclusions may be drawn as follows: 1) Nitroglycol poisoning in an investigated factory has passed a crisis apparently, but it seems to be not so hopeful that they are in a position, immune to moderate nitroglycol poisoning. 2) In order to make an earlier diagnosis of nitroglycol poisoning significant to prevent serious poisonings, an attempt of testing adrenocortical reserve functions on workers exposed to this chemical seems to be valuable.

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Time studies of women workers, workers for lunch service at primary schools, office girls, and keypunchers, were carried out in order to evaluate the difference of load in their work for 5 days from Monday to Friday. In the comparative studies among these different jobs, the motion of labor of the workers were surveyed and analysed every 30 seconds. The homelife and hours of sleep of the workers were investigated with a questionnaire to each worker every day. The results obtained are summarized as follows: (1) Such work as keypunching or office work was classified as mental work with light physical work, while the school lunch work was classified as light work, as evaluated by E.M.R. in terms of muscular labor. (2) Working hours of the workers for lunch service at primary schools, especially at schools located in the urban districts, were shorter than those of the other two. And also, hours of the actual labor of the workers for lunch service at rural schools were about an hour longer than those of the workers at urban schools. It was probably due to lack of dishwashing equipments in the cooking room of rural schools. (3) In actual working hours of the workers, there was considerable difference between keypunchers and the other two kinds of workers. The actual working hours of keypunchers were daily variable, for instance, the lowest value of their actual working hours was only 27.4 percent of their total working hours. (4) The rest time at home of the workers for lunch service was comparatively shorter than that of the other two kinds of workers. This is due to the difference of hours spent for domestic work among these three kinds of workers. The hours of sleep showed no significant difference among these three kinds of workers.

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The purpose of this study was to make clear the influences of the central factor to temporary threshold shift (TTS). Since we had found the sexual difference on TTS, this study was undertaken to know the relationship between the central factor and the sexual difference to TTS, too. We used the left ear of healthy 5 females and 5 males aged from 25 to 30 years for this experiment. When they were exposed to noise for inducing TTS, their psychological status were settled in 2 conditions; one is "relax" and the other is "attention". The "attention" condition was formed by the task aiming the target of the apparatus for describing the function of concentration maintenance (Takakuwa's apparatus). At the first experiment, exposed noises were continuous white noise (WN), puls noise (PN) and 4000 cps pure tone through the ear-phone. Duration of exposure was 3 minutes and exposed intensity was 40 dB in all the conditions. Test tones were 4000 cps at 40 dB exposure, and 4000 cps & 6000 cps at 90 dB exposure. At the second experiment, the exposed noises were of various intencities of 1000 cps and 4000 cps through the ear-phone. The duration of exposure in each experiment was 3 minutes. The test tones were 1500 cps at the 1000 cps exposure and 6000 cps at the 4000 cps exposure. The following results were obtained. 1) In the "relax" condition, the sexual differences on TTS and their recovery were seen at each exposure of the first experiment without pure tone 90 dB exposure, test tone 6000 cps. That is, TTS in the female was smaller than that in the male and their recovery in the female was more rappid than that in the male. 2) But, at pure tone 90 dB exposure, test tone 6000 cps, we could not see the sexual differences on TTS and their recovery. 3) At each exposure of the first experiment without pure tone 90 db exposure, test tone 6000 cps, in the male, TTS in "attention" was smaller than that in "relax", but, in the female, TTS was not significantly different between "relax" and "attention". 4) Both in the female and the male, at pure tone 90 dB exposure, test tone 6000 cps, TTS in "attention" was larger than that in "relax" and their recovery in "attention" was slower than that in "relax". The above-mentioned observations show the following points; i) The central factor affected TTS. ii) The effect of the central factor on TTS was changed by the difference of the character and intensity of the exposed noise. iii) Sexual difference was found in the mode of the effect of the central factor on TTS. 5) In the exposure of 1000 cps noise, TTS under "attention" was smaaller than that under "relax" at 80 dB exposure, and then, TTS under both conditions were similar at 85 dB exposure. On the contrary, at 90 dB exposure, TTS under "attention" was larger than that under "relax". 6) In the exposure of 4000 cps noise, TTS under "attention" was smaller than that under "relax" at 70 dB exposure, and then, TTS under the both conditions were similar at 80 dB exposure. On the contrary, at 85 dB exposure, TTS under "attention" was larger than that under "relax". By these observations, it became certain that the effect of the "attention" on TTS showed an inhibitory attitude at the low intensity exposure, but it was accelerative at the high intensity exposure.

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