22 
that the peroxidase in the alcohol mixture was killed at a temperature 
of 70° kept up for a few seconds, while in the mixture containing the 
ammonium sulphate the enzym was not killed after heating the mixture 
for a short time to 93° C. In the control solution the enzym was killed 
at 87° C. after three minutes. 
Griiss encountered in some vegetable objects an oxidase that resists 
the action of boiling absolute alcohol. He designates it as 7-oxidase. 
That such an oxidizing enzym exists which can resist even boiling 
absolute alcohol might appear strange. But when we consider that 
the action of absolute alcohol consists in the first place of depriving 
the objects of water, and, further, that dried enzyms resist a much 
higher temperature than enzyms in the moist or dissolved state, that 
observation loses its singularity. It may here be pointed out that 
recent investigations of bacteriologists have proved that certain kinds 
of bacteria also succumb much more easily to alcohol of 50 per cent 
than to absolute alcohol. Protoplasm of a high density which can 
resist drying is much less accessible to poisonous actions when dry than 
when moist.! The writer has also observed that the oxidase in the 
tobacco leaf resists a higher temperature when the leaf is itself warmed 
with some absolute alcohol than when the dilute leaf juice is. How- 
ever, a prolonged contact with absolute alcohol will doubtless kill 
the oxidase. Here, also, the peroxidase resists much better than the 
oxidase. 
CAN THE AMOUNT OF OXIDASE BE INCREASED BY SPECIFIC MANURING? 
Since Bertrand and Villiers have found some manganese is a regular 
ash constituent of the oxidases” and since it seems justifiable to attrib- 
ute to that circumstance an essential influence on the specific actions 
of the oxidases, it was of some interest to try to discover whether an 
increase of manganese in the soil would lead to an increase of the 
oxidizing enzyms in the tobacco plant. Therefore a 0.1 per mille soiu- 
tion of manganese sulphate was repeatedly used to water some tobacco 
plants, each of which received altogether 0.6 gram of that salt. The 
examination of the ripe leaf, however, showed no noticeable increase of 
oxidase and peroxidase on colorimetric comparison with the plants not 
so treated. Possibly the soil contained a sufficient amount of manga- 
nese for the formation of the normal maximum amount of these enzyms. 
A THIRD OXIDIZING ENZYM IN THE TOBACCO PLANT. 
The unfiltered juice of fresh tobacco leaves energetically decomposes 
hydrogen peroxide with evolution of oxygen. ‘The clear filtrate 
‘Also seeds resist a higher temperature when dry than when soaked in water. 
?Compt. Rend. vol. 124, pp. 1032, 1349, 1355. 
*’These experiments were conducted by Dr. E. H. Jenkins on the experimental 
field in Poquonock, Conn. 
