412 BOTANICAL GAZETTE [NOVEMBER 
the same extracts, it is evident that the peroxidase activity of pine- 
apple juice is not dependent upon the rate of decomposition of 
hydrogen peroxide. 
From the writer’s studies on the behavior of platinum black 
(Joc. cit.), in which it was shown that factors which influenced the 
catalase action have no effect on the oxidative activity, and from 
the fact that in certain stages of their development pineapples 
contain oxidases but no catalase, we may conclude that the sub- 
stances which effect the decomposition of hydrogen peroxide are 
not of necessity concerned with the enzymes which accelerate 
peroxide oxidations. It may be added that the fact that catalase 
is not universally present in living cells, as Lozw and others sup- 
pose, has considerable theoretical interest. 
LABORATORY OF PLANT PHYSIOLOGY 
Harvarp UNIVERSITY 
