4IO T. FURUTA. TOISONOUS ACTION OF QUIXONE. 



The highly . poisonous character of quinone became still 

 more evident by the observation that even in 0.005 P er rnillc 

 solution it killed tadpoles within one hour and thirty-five 

 minutes. 



Other aquatic animals (Asellus, Copepodd) were killed by 

 this highly diluted solution within eight hours. 



Conclusion : We can infer from all these results that 

 quinone is a very strong poison, — a much stronger poison indeed 

 than the other closely related benzene derivatives. In the face 

 of these facts does there exist any probable basis for the 

 hypothesis of Beijerinck, that the relatively large amount of 

 humus in the soil is due to the action of quinone ? It seems to 

 me that another hypothesis would be more natural than this 

 namely, that the quinone produced by Strcptotlirix chromogena 

 must be changed almost as soon as formed, for otherwise animal 

 and vegetable life in the soil becomes impossible ! 



