rg16] REED—OXIDASE AND CATALASE 411 
at atmospheric pressure.’ The glass wall of the tank allowed easy 
reading of the manometer. 
The curve AB (fig. 1) shows the rate of decomposition of the 
peroxide (as shown by the manometer readings) with the juice of 
the ripe fruit. Comparing this with AC of the same figure, which 
represents the rate of decomposition by the juice of the partially 
ripe fruit, it will be apparent that the latter has much less catalase 
activity than the former. Moreover, the juice of the green fruit 
showed no action on this concentration of hydrogen peroxide, or on 
a stronger solution, whether measured by the pressure method or 
by simply observing the evolution of bubbles of gas. As might 
be expected from these results, different fruits exhibit great varia- 
tion in their catalase activity, but in every case the juice of those 
in a more or less green condition showed no action in decomposing 
hydrogen peroxide. 
All of these fruits, however, showed approximately the same per- 
oxidase activity, as the following determinations indicate. From 
each kind of fruit ro cc. of juice was mixed separately with 100 cc. of 
2 per cent pyrogallol solution containing o.05 M hydrogen peroxide, 
placed in open beakers and maintained at 18° C. for two hours. 
The purpurogallin formed from the oxidation was then filtered off, 
dried, and weighed, after the method of Bacu and Cxopar. 
Comparing these results, stated in table I, with the previous 
measurements on the rate of hydrogen peroxide decomposition by 
TABLE I 
AMOUNT OF PURPUROGALLIN FORMED IN OXIDATION OF I00 CC, 
OF 2 PER CENT PYROGALLOL CONTAINING 0.05 M HYDROGEN 
PEROXIDE AND 10 CC, OF EXTRACT 
Peroxidase from Gm. pu —_—— 
Mile OUPAOUN Fre i es 0.986 
Seca ype PINCADDIE. 65 1.020 
Green Gam gd .. 
Contea: : bolted DHOPADONE. ooo ic eek 0.081 
5’ The 1 1 Py ae fe 
could not be satisfactorily employed under these cendtons, since the extract of the 
ferment had a reducing action on the permangana 
