The elimination rate of COHb in the blood was measured by a tonometer and the COHb saturation of the human blood under the exposure of 0.3% CO in the air for 30 minutes was estimated to be about 47%. The CO elimination of the tonometered blood by the exposure to 4 kinds of gases: 1ATA air, 1ATA O₂, 1.9ATA O₂ and 2.8ATA O₂, showed a linear decrease on the semilogarithmic figure, and the gradient coefficient (k) of the straight lines showed a good reproducibility and a significant difference from each other.
The COHb elimination after supplying a 0.3% CO air mixture for 20 minutes to 23 mongrel male dogs weighing 12 to 18kg was observed by letting them breathe 1ATA air for 300 minutes, 1ATA O₂ for 120 minutes, 1.9ATA O₂ for 60 minutes and 2.8ATA O₂ for 30 minutes. The COHb decrease of the CO-poisoned dogs showed also a semilogarithmically linear tendency and the gradient coefficient (k) among these four gas-breathing groups showed a significant difference.
The mean half-clearance time (t/2) of each group was: 1ATA air for 188 minutes, 1ATA O₂ for 32 minutes, 1.9ATA O₂ for 25 minutes and 2.8ATA O₂ for 12 minutes.
The higher the O₂ partial pressure in the inspired gas increased, the greater became the decrease of the COHb clearance time and the greater became the decrease of the half-clearance time. The CO elimination by the dogs at a high pO₂ was greater than that by the tonometer under the same pO₂, but at a low pO₂, on the contrary, a different relation was observed. This fact may be explained by the improvement of the ventilatory and circulatory functions of the alveoli concerned with the CO elimination at a high pO₂, but at a low pO₂ the alveolar functions are impaired by CO and the O₂ supply is insufficient to cover the dysfunction, so the CO elimination is greater in the tonometered blood than in the dog blood.
The procedure of OHP for CO poisoning was designed by the CO elimination rate in the dogs, assuming it to be the same as that in the human, for the patients of three levels of severity of CO poisoning: Phase I is breathing of 2.8ATA O₂ for 20 minutes, usually for the patients of each level of severity, then Phase II (breathing of 1.9ATA O₂) follows after that for deadly poisoning (COHb in the blood, 80%) for 57 minutes, for severe poisoning (COHb, 60%) for 46 minutes and for medium poisoning (COHb, 40%) for 32 minutes.
After the treatment of Phase II, the blood COHb content decrease to 5%, a safety level for CO poisoning.
This process is practical and effective for the OHP treatment of CO poisoning, and besides it is not only safe against O₂ poisoning but also is capable of supplying rapidly a sufficient amount of oxygen to improve the condition of the anoxic tissues.

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In the previous papers, the author has clarified that excessive intake of S-methylcysteine sulfoxide (methiin) extracted from cabbage caused splenic hypertrophy and anemia. The present study was undertaken in order to clarify these effects of methiin on rats fed a low protein, high protein or commercial diet.
(I) Male Wistar rats were separated into six groups and the following six different diet were given. Group A: a low protein (6% casein) diet, group B: low protein supplemented with 4% methiin, group C: normal protein (12% casein), group D: normal protein supplemented with 4% methiin, group E: high protein (18% casein), group F: high protein supplemented with 4% methiin. After 35 days, the rats werr sacrificed and various analyses were carried out. Red blood cell counts, hemoglobin and hematocrit in blood decreased and splenic weight and iron levels in spleen and liver increased in the methiin-supplemented groups B, D and F.
(II) Male Wistar rats were separated into five groups and the following five different diets were given for 50 days. Group A: a synthetic diet (15% casein), group B: synthetic diet supplemented with 2% methiin, group C: commercial diet (Oriental Co., MF), group D: commercial deit supplemented with 1% methiin, group E: commercial diet supplemented with 2% methiin. The data revealed that symptoms of anemia and splenic hypertrophy were seen also in rats fed a methiin supplemented commercial diet as well as rats fed a methiin supplemented synthetic diet.

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弗化水素酸(HF)の皮膚接触を受けたマウスの腹腔内に放射性グルコースを投与し,その接触時間によるグルコース代謝への弗化水素酸の影響を全身オートラジオグラフィーを用いて検討し,また同時に主要臓器中の弗素量の定量を行なった。その結果,次の諸点が明らかになった。
1) 脳についてはHF処理群における放射性グルコースからの放射性炭素の脳への取り込み率,脳中弗素量ともに対照群に比較し変化がなかった。
2) 肝,肺,腎皮質,血液の放射能はHF処理群において対照群と比較した場合,有意の上昇が認められた。
3) これに対してハーダー氏腺,口蓋腺,舌下腺,大腸粘膜はHF処理群において有意に放射能の減少がみられた。
4) HFの皮膚接触は投与された放射性グルコースの腹腔よりの呼吸能力を減少させた。

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In the ICR-JCL strain of mice, the influence of age on the susceptibility of mice to JE virus infection by intravenous route was investigated.
The mortality rate was the highest in suckling mice, and almost no mice survived. More than 60% of them died with severe intestinal hemorrhage.
In mice aged over 21 days, the mortality rate decreased, and it was within the same level in a group of mice of the same age, independent of the dose of virus administered in the range between 5 and 5×10⁶ smic LD₅₀. The rate of intestinal hemorrhage also decreased with age. More than 90% of the mice that survived age 21-180 days developped HI antibody 3 weeks after infection. The mortality rate was higher in the male mice of age 36-180 days. On the contrary, it was higher in female mice over 180 days of age.
Some of the mice infected with such symptoms, including severe loss of body weight, recovered and survived for more than 3 weeks. Among 45 sick mice of age 61-210 days, 9mice(20%) recovered.
Mice over 180 days of age, showed the lowest mortality rate of about 20 (male) and 30% (female) respectively. HI positive rate of the mice that survived was also the lowest (less than 80%) at this age.
In mice over 365 days of age, the mortality rate significantly increased as well as the HI positive rate of those that survived. And 96% of the mice that survived over 550 days of age showed a positive HI rate.
The results may imply that the higher mortality rate of mice by JE virus infection could be related to the ability of higher antibody response in young as well as in very aged animals.

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Studies of mental fatigue caused by exposure to the aircraft noise was carried out experimentally on 9 female students engaged in some intellectual performance. The tape-recorded noise of the flying Jet engine was controlled from 85dB(A) to 95dB(A) in the peak level. The subjects were exposed continuously to the noise during 50 minutes and 100 minutes, respectively, in an insulated room protected from general outer noise.
Through the noise exposure period, the subjects performed intellectual tasks, that is, the Kraepelin- Uchida's test and card-sorting test. At the same time, pulse rates and pulse waves of their fingertips were measured. Before and after each exposure, the mental fatigue was measured by the critical fusion frequency (C.F.F.), the color naming test (C.N.) and the discriminative reaction of the multiple performance test (M.P.). And the information of subjective sensations of human fatigue were collected by the questionnaire, Cornal Medical Index (C.M.I.) were used for psychophysiological complaints. The control data of each subject were obtained by the same experiment except noise.
The following conculusions were derived from observations. The grade of mental fatigue increased in the case of the noise exposure rather than in the case of the noiseless situation. In C.F.F., fatigue increased 13% under noise exposure of 50 minutes, 37% under that of 100 minutes. In C.N. and M.P. as wel as C.F.F. the same gradiance between the noise exposure and fatigue were found. Furthermore, fatigue revealed itself more clearly in C.N. than in C.F.F., namely, the rate of prolongation of the time required for color identifying exceeded the critical level of mental fatigue, while the rate of mental fatigue in C.F.F. was within the normal or allowable range.
The results of the questionnaire of subjective sensations of fatigue and of the C.M.I. in the case of the noise exposure showed no remarkable differences compared with those of the noiseless situation. But, it was found that some complaints of sensations of fatigue increased slightly during noise exposure compared with those in the noiseless situation. These complaints were the symptoms probably caused by the sympagotonic hypertension. Moreover, from the observation of the pulse rates and pulse waves, it was recognized that a biological lags of the relaxation of the sympathetic nerves system might occur when they were released from the intellectual tasks.
From the observation mentioned above, it is considered that there is a posibility of the inhibition of the learning effectiveness in school children when they are exposed to the aircraft noise such as the subjects were exposed to in this experiment. The exposed aircraft noise level used in this study, calculated from the peak levels and flying numbers, corresponds to 80 W.E.C.P.N.L.. It can be said that mental fatigue is induced markedly by the noise of 80 W.E.C.P.N.L.. It is suggested that the noise level of 80 W.E.C.P.N.L. is not harmless to human being in the case of intellectual performance, especially during school hours.

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振動に起因する障害の主所見には,手指の末端部の白指発作に代表される循環障害,神経障害などがある。循環機能の診断には,毛細管像,容積脈波,皮膚温,爪圧迫などの検査があげられ,一方,神経障害には,触覚,痛覚,振動感覚などの検査があげられる1)。しかし,これらの診断項目は,今なお,検討の段階ともいえる。
振動病の所見に痛覚鈍麻がある。これは一般に手袋型,靴下型など四肢末端分布型にあらわれる多発性神経炎2)に由来するといわれている。しかしながら,実際には常温下安静時には,このような痛覚鈍麻がみられず,寒冷下で,はじめて少々の外傷も気づかないほど,痛覚鈍麻が生じるという振動作業者も多い。このような対象者に検診をすすめていく場合,痛覚の常温下測定とあわせ,寒冷下に相当する冷水負荷下の測定も必要となろう。それでは,その冷水負荷をどのように条件づけるべきか,また,その結果,痛覚は冷水負荷によってどのように変化するのかの検討が必要である。
それらの点について,著者らは,山林チェンソー取扱者,特に白指有症者の痛覚閾値を中心に検討してみた。その結果,2, 3の知見をえたので,報告する。

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