56 BOTANICAL GAZETTE [JULY 
purpurogallin resulting from the oxidation of the pyrogallol was 
filtered off on asbestos under pressure, washed free of unoxidized 
pyrogallol, dissolved in 10 cc. of concentrated sulphuric acid, and 
the amount determined by titrating with o.05M potassium per- 
manganate. The results are indicated in the last column of table I. 
The amount of pyrogallol oxidized in 4 hours by different com- 
binations of potato and horse-radish peroxidase with potato oxy- 
genase is indicated by the amount of K MnO, required for titration 
(the greater the amount of KMn0O, required the greater the oxi- 
dation). It is evident that, like the Lactarius oxygenase, the 
potato oxygenase has some power to oxidize pyrogallol, but that 
this action is greatly accelerated by the peroxidase from the same 
source and to a less extent by that obtained from other sources 
(for example, from the horse-radish). 
~ These results furnish additional evidence in support of the con- 
clusion that all the direct oxidases consist of oxygenases plus peroxi- 
dases. Some tissues or extracts possess the indirect oxidase action 
(that is, they react only after the addition of a peroxide) and are 
capable of activating the oxygenases, hydrogen peroxide, or various 
organic peroxides, and it appears that they differ from those 
exhibiting direct action only in the absence of oxygenase or in 
' lacking the ability to regenerate oxygenase. 
’  Bacu and Cuopat’ consider that the oxygenases are formed as 
a result of an enzyme reaction or that they are themselves enzymes. 
Moore and Wauittey,’ while agreeing with the former investi- 
gators as to the occurrence of oxygenases, consider them to be 
merely unstable peroxides resulting directly from contact of atmos- 
pheric oxygen with various substances in the cell, such as BAEYER 
and VILLIGER (I.c.) have shown that benzoyl-hydrogen peroxide 
will form. The solution of this problem awaits further investi- 
gation. 
Whatever the origin of the oxygenase may be, it is clear that 
there is a substance, peroxidase, possessing enzyme properties, 
and capable of transferring oxygen from oxygenases (or from 
peroxides of known constitution) to oxidizable substances. The 
7 Ber. Deutsch. Chem. Gesells. 36:600-605. 1903. 
® Biochem. Jour. 4:136-167. 1909. 
