is conceivable that the catalase itself. K. might be more readily 
oxidizable than guaiaeum or any of the peroxidase reagents, in 
which event we would have — . 
H a AD, = H,0 + KO. 
This would explain the fact that while powerful catalysts, the catalases 
are not unlimited in their power to effect the decomp c si: i n of hy- 
drogen peroxide. In this connection it is of interest to note that 
Senter 4 ' :: found blood-catalase hemase to be oxidized at all tem- 
peratures above 0° C. It is easier, however, and more in harmony 
with what we know regarding the conduct of other catalysts, to 
suppose that both of these changes would occur simultaneously, viz. 
H,AD,= A’+ILO-f O. 
and 
EL AD 2 — Guaiacum = K— H O — Guaiacum-blue. 
in which event the given substances would exhibit the properties of 
both a catalase and a peroxidase: and it may be after all. that when 
examined more closely, the catalases will show peroxidase reactions. 
As it is. the two sets of substances, if they are really distinct, are 
certainly found in the closest and most intimate association in both 
plant and animal tissues. 
