1903.] 



Benzene in Poisoning hy Coal Gas. 



79 



apparatus were employed, so that the influence of two gases could 

 be compared at one and the same time on the two sartorii of the 

 same frog. 



When coal gas was led through the tube the muscle began to 

 contract 1 — 7 minutes after the beginning of the passage of the 

 gas, and in \ — 1 hour the muscle was maximally contracted and had 

 an opaque appearance. The rapidity with which the contraction came 

 on was proportional to the rapidity with which the gas was passed 

 through the chamber, and varied with the temperature, warmth 

 quickening and cold slowing the process. Once the muscle was fully 

 contracted no recovery took place. This phenomenon could not be 

 due to the CO in the coal gas, since, on passing pure CO through the 

 muscle chamber, the muscle remained excitable as long as in nitrogen, 

 and the fatigue curve took the same course as in that gas. Among 

 the remaining more important constituents of coal gas which might 

 produce this phenomenon, benzene merited first attention, since all 

 aromatic bodies are more or less potent poisons. I therefore tried 

 the effect of passing air through benzene into the muscle chamber. 

 I found that in less than a minute the muscle began to contract, and 

 the contraction reached its maximum height within a short time, the 

 muscle becoming opaque and dead. The other sartorius of the same 

 frog was placed at the same time in coal gas. It began to contract 

 only after several minutes, and the contraction took half an hour to reach 

 its maximum. Benzene vapour therefore showed itself much more 

 poisonous for a muscle than coal gas, evidently on account of its 

 greater concentration. According to Letheby, London coal gas 

 contains only 3*8 per cent, of condensible hydrocarbons, of which 

 benzene forms only a small proportion. I therefore, in another 

 experiment, passed air into the muscle chamber, not through pure 

 benzene, but through water which had been shaken up with benzene. 

 In this case the contraction began 6 minutes after the beginning of 

 the experiment and took 38 minutes to reach its maximum, while the 

 control muscle in coal gas began to contract in 7 minutes and reached 

 its maximum contraction in 40 minutes. 



It seemed, therefore, highly probable that benzene was really the 

 constituent of coal gas which was responsible for its toxic properties 

 on muscle. If that were the case the passage of coal gas through oil, 

 which absorbs benzene, ought to deprive it of its deleterious effects. 

 This was found to be the case. Coal gas, passed through oil, showed 

 no difference in its effects from pure CO or nitrogen. 



In the same manner as benzene I investigated the effects of xylol 

 and toluol. If the muscle was supplied with air blown through either 

 of these fluids no poisonous effect was observed even when the fluids 

 were warmed. The absence of effect in these two cases is perhaps to 

 be ascribed to the lower vapour tension of these two substances. The 



