ON THE POISONOUS ACTION OF QUINON?:. 409 



stain quickly by highly diluted methylene blue. It was thus 

 found that diatoms and the cells of Mesocarpus were killed by 

 quinone in three hours and forty minutes ; soon afterwards also 

 Spirogyra. Towards algae hydroquinone also proved very 

 poisonous ; indeed with diatoms hydroquinone acted nearly as 

 powerfully as quinone. With resorcin, pyrogallol, and phloro- 

 glucin, death was observed more than a day later. 



Experiments with Mould Fungi and Bacteria. 



Penicillium glancum developed on beerwort to which 1 per 

 mille quinone had been added, while Aspergillus oryzae did not. 



Bacteria were inoculated in bouillon to which after steri- 

 lization 1 per mille quinone had been added. The bacillus of 

 typhoid fever of mice could not develop in this solution, while 

 Bac. pyocyaneus gave a meager growth on the surface. 



Experiment with a Mouse :— 



The vapour which quinone emits at the ordinary temperature 

 exerts a highly poisonous action on warm blooded animals. 



About 1 gram of quinone was placed in a deep beaker glass 

 liter capacity) and upon this at a height of 3 cm. above the 

 quinone a wire gauze was placed. A small white mouse was then 

 put in the beaker glass and this covered with a glass plate, which 

 was often lifted to admit fresh air. The animal became at once 

 very much agitated, tried to escape and soon^gave evidence of 

 irritation of the eyes and nose. After one hour all the motions 

 became sluggish, and after two hours more the animal was dead. 



Under the same conditions horse-flies died within three hours. 



Experiments with Tadpoles. 



Tadpoles were placed in the o. 1 per mille solutions of 

 quinone, and the time required to kill the animals was : 



(I) 



with quinone : 



33 minutes. 



(2) 



,, hydroquinone : 



58 „. 



(3) 



,, pyrocatechin : 



22 hours and 23 minutes. 



(4) 



pyrogallol : 



3i .. 13 



(5) 



,, resorcin : 



54 „ S3 



(6) 



phloroglucin and control (plain water) : they 



still actively moving after six days, 



