The problem of absenteeism is the long standing task by the International Committee on Occupational Health. In Japan it is now also being studied under special Research Committee established for the purpose. 1. Results investigated of absenteeism percentage 2. Difficulties in the preparation of statistics of absenteeism 3. Author's opinions 4. Conclusions The accurate statistics of absenteeism is looked upon as the reflexion of the hygienic conditions in factories and thus most important for industrial hygiene. For the purpose of comparative study among various statistics, it is necessary that some uniform method of compiling the statistical data should be employed not only in one country, but also among all the countries in the world. However, this has been not yet realized. For this purpose, it is hoped that such a form to be used among the nations will be prepared with the cooperation of the colleagues attending this conference.

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The oscillation of the 3rd lumber spine of 9 adult women washing a dish on sinks of various heights were continuously recorded by a kimo-graph. 1) The lower the height of the sink is, the greater the shift of the posture and the amplitude of curves are also increased. 2) The limits of heights of sinks are determined by various factors; acrominal heights, the length of upper limbs, the height of hips, the depth of umbilical region, the distance of subjects from sinks and the habitual way of each individuals. 3) In case of smaller women the adjustments to the heights sinks are mainly performed by the elbow joints while the adjustments by the hip joints while the adjustments by the hip joints are done in case of the taller subjects. 4) The upright posture with the bending elbows (95°∼130°) is tolerated for a long-time with the minute amplitude of curves, while bending hip joints with the stretched arms causes the pain of waists, with increased amplitude of curves. 5) The subjects standing 15cm. backward from the original site could hardly take an adequate posture as the fat woman.

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The finishing and inspecting process of cotton cloth at spinning mill is a job performed by female workers who keep standing and do not shift their position. Moreover, the job requires the workers' steady gaze. From this point of view, the change of asthenopia and circumference of their lower legs while working in a spinning mill, particularly, are examined. 1. The average bodily size and power of these workers are: height 153.53cm, weight 52.82kg, circumference of chest 83.05cm, Vervaeck's index 88.69, visual vision 1.42 (left), 1.30 (right), grip 24.00 (left), 23.88 (right) Thus, in all the items of the list (exceptgrip ) the workers are superior to the average girl students of high schools in Japan. In grip alone the former is somewhat inferior to the latter. 2. By means of flicker test their asthenopia has been investigated. The results obtained indicate that the further the job progresses, the more the fatigue increases. This is ture of both the 1st and 2nd shifts. (The job is done in two shifts) Buta greater degree of fatigue is shown by the 1st shift. The explanation seems to be that the 2nd shift which starts the job much later than the 1st shift naturally stay longer at home and so have their asthenopia more accustomed to activity, hance less fatigue. 3. The swelling of lower legs resultant from the job is caused to both the shifts and both side legs, and increases with the progress of the work. But the bulging has been found to be greater among the 2nd shift. The reason is probably that the 2nd shift stay longer at home before the job than the 1st shift, 2nd so perform a larger amount of household work, perhaps in standing posture. To sum up, worker's fatigue at spinning mill is that resultant from light labour below medium degree. However, the job being done in shifts the fatigue is much aggravated, if they do not take enough rest or their mode of life if inadequate at hame before setting about the job.

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Health maintainance program against mercury poisoning in a tungsten rod manufacturing factory was done from Spring 1957 to Summer 1958. At first, mercury concentrations in work room air were between 0.3 and 1.0 mg/m³. After the lapse of about half a year, modification of tungsten treating bottle, which was the main source of mercury exposure, installment of local exhaust fans and reformation of room ventilation was done. Then, the mercury concentration of air dropped below 0.1 mg/m³. In accordance with the decrease of mercury concentration of air, s ymptoms of mercury poisoning in workers partially disappeared and partially remained. (1) Decrease of mercury concentration in worker's urine was parallel to that in air. No difference of mercury concentration in urine was found between a group of longer duration of employment (over 2 years) and another of shorter duration (under half a year). Some of the workers were transferred to other place free from mercury exposure, the mercury concentration in their urine dropped below the level of other workers not transferred. But, soon after return to the former place, the mercury concentration in urine was found to be near the latter. (2) According to one short term exposure (for six hours, 0.7-1.0 mg/m³), the excretion of mercury in urine became highest in 3 hours after cease of exposure. (3) Microhematuria and proteinuria were found, especially in the group of shorter duration of employment, when mercury concentration of air was between 0.3 and 1.0 mg/m³. (4) Stomatitis, tremor and erethism were found, especially in the group of longer employment. On these symptoms the change of mercury concentration of air had scarcely influenced. (5) Increased excretion of coproporphyrin and urobilinogen in urine was found in about 80% of workers during this observation. (6) Results of PSP excretion test were normal in all the workers on examination in March, 1958.

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Hematological studies on the chronic CCl₄ poisoning were performed in thirteen female rabbits, which were divided into five controls and eight CCl₄ injected group. The CCl₄ animals were administered with the poison three times a week by subcutaneous routes in the dose of 0.022 cc CCl₄ per kg. body weight which was determined by the previous study. Three of CCl₄ poisoning group were used for histological observation at about first month from the beginning of the experiment. The examinations were made approximately once a week concerning the following items; body weight, red blood cell and leulocyte count, hemoglobin content, hematocrit value, icteric index, color index, volume index, average diameter of erythrocytes, osmotic fragility of red cells, plasma volume, serum iron level, organ iron contents, weight of organs and microscopic examination of organ tissues. The results obtained were as follows: 1. The average body weight of controls increased gradually more than the CCl₄ group which kept on constant level along the course of the experiment. 2. Red cell count, hemoglobin content, leucocyte count and hematocrit value in CCl₄ group ran parallel with each other, and all of them showed two peaks throughout the course. 3. The icteric index of CCl₄ group was maintained on a higher level than that of controls. In the course of the experiment it was highest in the earlier stage of intoxication. 4. In the poisoned group the average diameter of red cells, color index and volume index were increased. 5. The osmotic fragility of red cells in the CCl₄ group showed a tendency to reduce after two weeks. 6. The plasma volume as well as the blood volume of CCl₄ group had a tendency to increase gradually. 7. The serum iron level in the CCl₄ group increased gradually and reached its highest level at the third week. 8. Evidence of changes in iron content of organs of the CCl₄ group was not found. 9. The liver of poisonned animals gained in weight in the beginning, but decreased at the end. The weights of the poisonned spleen and kindey were increased and that of the poisoned heart decreased. The most characteristic gain of weight, however, was found in the adrenal gland. 10. Concerning microscopic findings of organ tissues, the most marked change was found in the liver, which showed earlier features of cirrhosis during the first month of the poisoning and at the end of the experiment a progressed, definite liver cirrhosis was revealed. The bone marrow tissues were microscopically hypoplastic at the first month, but they became hyperplastic at the end.

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The ventilatory function was discussed in this paper in analysis of a discrimination. The subjects were about 500 ceramic workers, ranged 45 to 60 years of age. Thirty slight silicosis were selected out of them who revealed nodi sporadically in the central field of the lung in roentgenogram. The other 30 cases who had no specific findings roentgenographically were taken as a control. Factorial elements used in discrimination analisis were X₁, X₂ and X₃, namely the value of the maximum breathing capacity, load index and air velocity index, respectively. The discrimination formula obtained were Y=0.016X₁-0.1446X₂+0.0242X₃ The individual discriminants were culculated by use of the above formula in all cases. The mean value of the discriminants of the control group was 8.68, while it was 6.82 in the silicosis cases. It indicated that the ventilatory function impaired in silicotic cases than that of normal control cases. When the screening was done by the rejection limits produced by the all individual discriminants, only one case was checked as an abnormal in the control group, while 11 cases was checked as an abnormal in the control group, while 11 cases were checked in the silicosis group.

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The author made rabbits inhale dust of coal from Sakito Mine, Kyushu, and the coal dust mixed with the equivalent quantity of dust of the bed rock of the colliery, to cause experimental anthracosis and anthraco-silicosis in them, for comparative study of the pathological pictures in them. Next, the dust-inhaled rabbits were inoculated with low virulent bovine tuberculous bacilli for causing concurrent lung tuberculosis in them and comparing the findings with those of simple tuberculous controls the influence of anthracosis and anthraco-silicosis on complicated pulmonary tuberculosis was investigated. The results of the experiments were in summary as follows: 1) In the rabbits made to inhale coal dust, the principal findings were deposition of coal dust and cell proliferation at the sites of coal deposition, accompanied by mild proliferation of argyrophil fibres, but no long-standing proliferation of collagenous fibres was observed even in the experimental animal kept under observation for the longest time. 2) In the rabbits made to inhale rock-dust added coal dust, beside the above findings, distinct silicotic granuloma formation due to proliferation of collagenous fibres was apparent. 3) In the rabbits made to inhale coal dust and subsequently inoculated with tuberculosis changes were found perceptibly more aggravated than in the simple tuberculous controls, but in some cases the parallelism between the grade of the anthracotic changes and the tuberculous changes was not apparent. 4) In rabbits made to inhale coal dust plus rock dust and subsequently inoculates with tuberculosis bacilli, the tuberculous changes were found particularly aggravated. In these cases, the tendency to occurrence exsudative or necrobiotic changes in the tuberculous foci was always found the stronger, the severer the anthraco-silicotic changes. From such experimental results, it may be concluded that even coal dust devoid of the effect of causing proliferation of fibres or an thracosis due to such coal dust acts in aggravating the tuberculous changes occurriug in complication, but this effect of coal dust is weaker than that of coal dust mixed with silicate dust.

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