Recent development of the methodology of occupational cancer research was reviewed, in regard to the experimental and epidemiological approach. The author's attention was directed toward the evaluation of the results of animal experiment, particularly toward the standardization of carcinogenic potency, presented by Horton and Denman. Concerning the epidemiological methods, a paper prepared by the Committee on Occupational Cancer of Council of Industrial Health, U.S.A. 1948 was chiefly introduced. A result obtained by the present author was also quoted, comparing the date which showed about a double high "relative frequency" of lung cancer among workers in chromium and nicickel industries in comparison with the expected, to the other which resulted in the same conclusion by means of the computation of age adjusted death rates from the same material. In the latter, the observed lung cancer deaths were compared to the expected, calculated from the population record in the same year, and showed again significantly a higher figure (p=0.01) in the above mentioned industries. The result implies that the "relative frequency" would be useful when the denominator for computing a death rate is not available, although there are some limitations. Biochemical studies on the induction of the bladder cancer, developed by Bonser, Boyland and others were discussed, with ultimate hope that ideas akin to this in the study of occupational cancer would lead to the elucidation of other "natural cancers" among human beings. Finally the author did not forget to add that studies in this field be much more vigorously promoted in this country in light of rapid development of industrialization.

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Hippuric acid excretion in the urine of workers after exposure to toluene, was assayed by Gaffney's method. The results obtained are as follows. (1) The determination of hhippuric acid in the urine was carried out by paperchromatography, spoting 0.1 ml of urine on the filter paper (40×40 cm) which was (developed in a solvent system: butanol, acetic acid, and water, (4: 1: 1). After drying, the color reaction was brought to completion, by spraying with 4 per cent solution of p-dimethylaminobenzaldehyde in acetic acid anhydride saturated with sodium acetate, and by heating in a drying oven for one minute at 135°C. The Rf value of hippuric acid contained in the urine was 0.8 coincided with that of pure hippuric acid. The absorption spectrum of the methanol eluate of the colored spot of the workers' urine corresponded also with that of pure hippuric acid. (2)The hippuric acid excretion in men administered orally with sodium benzoate showed the maximum value one hour later and ceased 4 hours after the administration. (3) In a plastic manufacturing factory using toluene as a solvent, a group of workers exposed to 50p.p.m. of toluene in the air excreted hippuric acid as much as 3.4 times the pre-exposure value, and in another group exposed to 20 p.p.m. it was 1.9 times. These results may indicate that excretion of hippuric acid in the urine is proportional to the concentration of toluene in the air. (4) At an autotricycle factory using the mixture of toluene and benzene (4:1), an increase of hippuric acid excretion in the urine of workers was recognized after exposure to this gas mixture.

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ネコにニトログリコールを筋肉内注射した場合に脳波,血液中のメトヘモグロビン,脈搏数の3者がいかに変化するかを追究した。ニトログリコールの投与量は250mg/kgと100mg/kgの二つで,いずれも10%オリーブ油溶液として筋注した。 脳波にみられた変化はどの投与量の場合にも質的に類似しており,第一に注射直後の扁桃核での高振巾徐波の出現,第二に注射後30分(250mg/kg投与例)または60分経過後(100mg/kg投与例)にみられた全脳波(海馬,扁桃核,新皮質)の平低化が特記すべきものであった。 この全脳波の平低化は血中メトヘモグロビンが60%に達した後にみられ,おそらくメトヘモグロビン血症に由来するHypoxiaによるものと考えられた。他方,扁桃核にみられた初期の変化にひき続いて海馬の規則的な徐波の振巾の減少がおこったことから,扁桃核-視床下部の系への侵襲がニトログリコール急性投与時の特徴ある変化と考えられた。

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