A survey has been made on cases of occupational accidents occurred in a (non-ferric) metallic mine three years from June 1956 to June 1959. The results can be summarized as follows. 1. Incidence rate of accidents especially of minor accidents in increasing from year to year. 2. While rock pieces falling from the ledge, wagons, rolling or flying pieces of rock are main agents of accidents inside the mine, mineral and other materials, machines and tools occupy most of the agents of accidents outside the mine. 3. Of all the accidents 75 per cent have occurred in miners working inside the mine, among which "direct" laborers have accident rate 2 to 3 times as much as "indirect" laborers. 4. Parts of the body suffered most from the injury for all the workers are in the order: upper extremities, lower extremities, head, and trunk. But, in so far as accidents inside the mine concern, trunk injuries come to the third. 5. The day when accidents occur most is the first day after the off-day and the fourth day comes next. Accidents occur most three to four hours after the commencement of work. Therefore, increase of fatigue, decline of attention, and deterioration of enviromental conditions accompanying the increase if intensity, density, and speed of work are considered to be the causes of accidents. 6. Incidence rate is highest in the age group of 45-50 years. As to the length of employment, the rate is highest in enployment less than six months, and 15-20 years come next. 7. The more overcrowded employers' dwelling conditions, the higher the rate of accidents. 8. Those who has suffered from accidents twice a year and more have been looked upon as accident-prone.

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As one case of B H C dermatitis with marked signs was found, an investigation was carried out on B H C hazards among workers of a B H C manufacturing plant. It was found that the rate of incidence was 28%. 70% of all the cases occured within six weeks after placement, and 45% of all the cases took place between four and six weeks. Individual difference of sensibility was seen, but those, who had been once afflicted with dermatitis, never suffered from it again. The chief symptoms of B H C dermatitis were light red, miliary eruptions which conglomerated sometimes into speckles forming blisters or eczema at last. It could not be determined experimentally which one of four isomers of B H C caused dermatitis.

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Blood, urine, blood pressure and subjective symptoms of 32 workers in a B H C plant were examined in order to investigate B H C hazards. Slight anaemia, leukopenia and eosinophilia were found in about 40% of the examinees and number of items of subjective symptom increased in proportion to the length of service. However, it is natural to think that these findings were solely due to B H C poisoning, because such changes in the blood are found in common among workers of any other plants and many parasite egg-holders were found among the examinees. Findings on three workers who were suddenly attacked with loss of consciousness, weakness of muscle and convulsion were reported here. Besides these chief symptoms, leukocytosis and neutrophilia were observed in the blood. These cases were diagnosed as B H C poisoning.

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A colorimetrical procedure as a simplified method for the determination of so-called Fujiwara-reaction-positive metabolites of trichloroe thylene in urine was studied. The procedure is summarized as the following. The mixture containing 2.0. ml·of urine, 2.0 ml of 50 g/dl sodium hydroxide solution and 10.0 ml·of pure pyridine is shaken, and the mixture is then immersed for 15 minutes (12∼15 minutes) in a water bath at 70°C. Being cooled by running cold water for 1 minute, the colored pyridine layer is diluted twice of five times with 1:1 pyridine-water mixture. Colorimetry should be done within 5∼15 minutes at 530 mμ against the blank, control which has been prepare similarly starting from 2.0 ml·of water. The plug of cotton wool containing a piece of dry potassium hydroxide is not necessary during the whole procedure. The range obtained with this method reaches 80 mg/l when the pyridine layer is diluted twice, and 300 mg/l when diluted five times.

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The method of determination for alcohol-type-metabolites among trichlorcethylene metabolites in the urine was studied. The procedure is as follows. The mixture containing 1.0 ml of urine and 5.0 ml of pure toluene has been shaked for about 30 seconds, 4.0 ml. of the toluene layer is pipetted. To this toluene layer, 4.0 ml of sulfanilic acid solution (1.0 g of sulfanilic acid dissolved in 200.0 ml of 1:200 hydrochloric acid solution), 1.0 ml. of sodium nitrite solution (0.7 g of sodium nitrite dissolved in 100.0 ml of distilled water) and 1.0 ml of sodium hydroxide solution (4.0 g of sodium hydroxide dissolved in 100.0 ml of distilled water) are added and shaken, and this mixture is then heated for 15 minutes at 60°C. at quiet. After cooling the muxture in running cold water, the next step of the procedure should be done on it immersed in ice water. That is, the colored layer is diluted to 2:1 ratio with distilled water, and colorimetry is done at 510 mμ as soon as possible. The range obtained with this method reaches 300 mg per 100 ml of the urine.

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It is thought that trichloroethylene metabolites are divided into three kinds, that is, so-called Fujiwara-reaction-positive metabolites, alcohol-type metabolites and those glucuronides. According to the findings about trichloroethylene workers and narcotized women with this, in whom the quantitative relation between Fujiwara-reaction-positive metabolites and alcohol-type-metabolites in urine was different individually, the effects of glucuronic acid to that relation involving glucuronides of those metabolites were studied on rabbits exposed to trichloroethylene experimentally. It was noted that, when capacity of detoxication was thought to be improved by the administrations of glucuronic acid, the amount of Fujiwara-reaction-positive metabolites decreased while that of alcohol-type-metabolites increased.

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A health examination was done on 17 workers engaged in painting with benzene mixtures. Items of the examination were counting of red and white blood cells, tests of protein, urobilinogen, and copropora phyrin in the urine, questioning to fellings of fatigue, headache, vertigo, general weakness, and intestinal disorders. Subjective symptoms were positive in many of them. In a few of them decreased blood cell counts and positive urobilinogen were found. Positive albuminuria and coproporphyrinuria were not found in any of them. On five subjects who had many subjective symptoms and showed decrease of blood cell counts, measurements were made as to relative number of constituent leucocytes, specific gravity and hemoglobin content of the blood, sugar and urobilinogen contents in the urine, just before, one week after, and at the end of the intravenous administration of thioctic acid of 25 milligrams a day for two weeks. During these two weeks marked increase of the red and white cell counts, specific gravity of the whole blood, and hemoglobin contents as well as marked decrease of urobilinogen out-put in the urine were noted. But, there was no improvement of the relative counts of the leucocytes.

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Machines and tools in a work situation should be within the reach of arm movements of the operator in his sitting posture. In other words, the operator should not be required to leave his normal working position to operate his machine. The normal working area and maximum working area of the arm in three dimensions were measured. The equations related or a nomograph was constructed from the measurement data, from which can be known the necessary values associated with the total span. This nomograph would be of aid to designers of various industrial machines. In arm movement the shoulder or elbow does not stay at a fixed point, but rather moves outward or upward. The movement of the scapula occurs with that of humerus. The arrangement of controls in the working area should be evaluated also from other aspects.

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For the purpose of clarifying the significance of Ca-EDTA as an accelerator of heavy-metal excretion, the interactions between albumin and heavy-metal ions and the effect of Ca-EDTA upon the combination of the metal with albumin were studied under various conditions by polarography. EDTA and Ca-EDTA were found to have the ability to combine with Cd, Pb, and Mn stoichiometrically at pH 7.0, and the complexes were stable. Cadmium combined with bovine serum albumin at the imidazol group, but this combination was inhibited by Tris (Hydroxymethyl) aminomethane. Combination of plumbus ions with albumin was completely inhibited by tartaric ions. EDTA and Ca-EDTA reacted also with the cadmium or lead combined with bovine serum albumin.

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In the air of workshops, there very frequently exist benzene, toluene and xylene vapors in mixture, but it is difficult to quantitatively determine each of them from the mixed vapor, while it is important because benzene is more toxic than the other. The determination was done by means of gas-chromatography. 1) First, the method of quantitative determination of benzene, toluene and xylene in solvent was studied. The most suitable condition in the gas-chromatography was as follows: Stationary phase D.O.P 200cm Column temperature 125°C Sample inlet temperasure 145°C Carrier gas Hydrogen Gas flow rate 40ml/min Detector 64-128mV Sensitivity 100mA Sample quantity 0.02-0.05ml The minimum determinable concentration of solvents by this method was 0.1% and the error was within 0.5% of the value determined. 2) As to the quantitative determination of benzene, toluene and xylene in air, the method to analyse colorimetrically after their separation by gas-chromatography is accompanied with gross error and of no practical use, because the vapors are condenced near the outlet. 3) When the air was supplied into the gas chromatograph without any procedure, the minimum determinable value was about 75 p.p.m. for 100 ml. of air, which is the muximum amount that can be supplied. 75 p.p.m. is too high to be the desirable minimum value. Hence a concentration process is required for the quantitative determination of benzene, toluene and xylene in the air. 4) In order to concentrate benzene, toluene and xylene in the air, one liter of air was passed at the rate of 100 milliliter a minute through a small column filled up with 1 gm .of solid support (DOP) and cooled by dry ice. By such a procedure, the column showed a good retentive capacity, and the result was satisfactory even when two liters of air was passed at the same rate. 5) In order to keep from the disturbance by steam, it is necessary to set phcphorus pentoxide column before the concentriation column during air-sampling. Silicagel and molecularsieve are inadequate as desiccating agents, because these also absorb benzene, toluene and xylene as well as steam. 6) When the concentration column including benzene, toluene and xylene are attached to the inlet of the gas-chromatograph and heated at 130°C, their vapors are sent quickly into the gas-chromatograph with carrier gas. Thus a satisfactory gas-chromatogramm is obtained. 7) In the quantitative determination of benzene, toluene and xylene vapors in air, the adequate column temperature is 100°C instead of 125°C as applied to the analysis of solvents, because at 125°Cthe vapors are not separated sufficiently from steam. The desirable flow rate of the carrier gas is 60 ml/min in consideration of the extention of the retention time that follows the fall of the column temperature. The other conditions are the same as the analysis of solvents, except for changing of sensitivity to 2 mV. 8) Quantitative determinations by the method mentioned above were made in air samples including benzene, toluene and xylene vapors in the known concentration. The results indicated that the method was fairly accurate. 9) The minimum determinable concentration by this method applying one liter of air is apploximately 2 p.p.m. for benzene, 4 p.p.m. for toluene and 10 p.p.m. for xylene, and these are equivalent to about 0.003 mV (4mm) in the peak height of gas-chromatogramm. 10) In application of this method to the field measurment, the air samples are taken into the concentration columns with phoshorus pentowide columns. They are maintainable for a long time if the columns are corked tightly. It is also desirable to know previously what kinds of substances with low boiling point exist together, because they may disturb determination of benzene, toluene and xylene.

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Experiments were carried out to discover the horizontal and veritical distribution of the hand strength pushing horizontally a knob by adduction of the upper limb and the effects of the posture of the subject. To measure the strength a straingauge dynamometer was used, the knob of which was (pushed horizontally.) with right hand by six female adults. The results are: 1) The most effective position of the knob is at 22.5°∼45° left side of the right acromion and near the front of the body. 2) In the standing posture with legs apart the performance is better and the best result is obtained with the knob placed relatively high. In the sitting posture, the lower the seat height, the better is the performance. 3) Generally speaking, the performance depends on the force spent for maintaining the posture, rotation of lower limbs, and the friction between the surface of floor and soles of feet.

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