In order to make clear the toxicity of two kinds white gasoline containing tetraethyl lead (LG) and organic solvents besides tetraethyl lead (LBTX), the survival rate and the electrocorticogram (E.Co.G.) in rats injected with either of them intraperitoneally were analysed.
Thirtynine white male Wistar rats, weighing about 400 g and aged 7 months, were implanted with bipolar electrodes on the surface of the brain about 3 mm apart over the frontal and occipital lobes of the left hemisphere under Nembutal-ether anaesthesia. The rats were divided into two groups, each rat in one of them was intraabdominally injected with 1 ml/100 g of LG and each rat in the other with the same dosis of LBTX. Tetraethyl lead content of LG was 1. 0 ml/liter that is, 16.5 mg/kg body weight of rat, and LBTX contained 5% benzene, 10% toluene and 15% xylene and 70% LG, tetraethyl lead in LBTX becoming 11.6 mg/kg body weight of rat. RG and HG, used in the former experiment, are commercially available leaded regular and high-octane gasolines. Tetraethyl lead contents of RG and HG were 0.15 ml/liter and 1.41 ml/liter, i.e. the amount of tetraethyl lead in rat were 2.5 mg and 23.3 mg/kg body weight respectively.
Observations were made one month after recovery from the implant operation. Brain waves were recorded on one day before and at 1, 2, 3, 4, 5, 7 and 10 days after the injection. The original wave, the momentary waves of δ, θ, α, β₁ and β₂ in the E.Co.G. and each 10 second integral value of these brain waves were recorded at the same time, and the data for 5 to 10 minutes were analysed.
One to 4 days after the gasoline injection rats showed slowing of movements, a crouching posture and absence of reaction to stimuli. After fifth day from the gasoline injection, the rats in the LG group showed excessive tension, excitement and anxiety, and the rats in the LBTX group showed continuously the same symptoms as crouching posture and slowing of movements. But about half of the rats in the LBTX group showed delirium and were dead within 2 days after LBTX injection, while almost of the rats in the LG group were alive. The death rate of HG and LG group was similar with LBTX group.
The control E.Co.G. before the injection showed a dominant θ and marked α waves, and the amplitude of these waves ranged from 50 to 150 microvolts. One to 5 days after the gasoline injection the basic rhythm and the amplitude in the E.Co.G. decreased and this phenomenon was more marked in the LBTX group than in the LG group, that is, α wave on the 1st day, δ and β₂ waves on the 4th day and θ wave on the 5th day after the gasoline injection decreased significantly compared to those of the LG group. The α wave of the rats in the LG group increased markedly and dominantly 7 days after the LG injection. The E.Co.G. of rats in the serious state before death caused by LBTX showed high voltage fast waves, arhythmic pattern of the brain waves appearing and disappearing, and slow and fast brain waves.
From these results it was concluded that the toxicity of LBTX was stronger than that of LG.

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Four cases of atypical elemental mercury poisoning are reported each of which showing a sudden increase of urinary mercury excretion, which lasted for about 6 months, after 18th month from the exposure, although urinary mercury concentrations had been gradually decreased until 17th month after the mercury vapor exposure. The characteristic features such as tremor and kidney symptoms usually seen in elemental mercury poisoning were not observed in our four cases. Some patients showed concentric constriction of visual fields, hearing damage in high frequencies, ataxia and peripheral neuropathy which were frequently seen in the alkyl mercury poisoning. But, these signs were considered to be related to mercury vapor exposure, although some other agents might have produced such unusual symptoms. The reason for the sudden increase of urinary mercury for many months after the exposure was not explained in the present study.

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Distribution of toluene in mouse tissues was investigated by the gas chromatographic measurement after injection of toluene and by radioactivity assay after injection of ¹⁴C toluene.
The results obtained are as follows.
1. The concentration of toluene measured by gas chromatography was in the descending order in the tissues : kidney, liver and cerebrum. Toluene decreased more slowly in the cerebrum.
2. Higher radioactivity in the cerebrum than in the blood and the highest in the adipose tissue were observed after the injection of ¹⁴C toluene.
3. From the above results, it is concluded that toluene has high affinity to the cerebrum containing high lipid fraction and also to adipose tissues.

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