282 BOTANICAL GAZETTE [APRIL 
oxide. Sodium and potassium hydrate oxidized the aloin slowly. 
Copper sulphate plus sodium chloride oxidized aloin solutions 
immediately. On the organic side, benzaldehyde, quinone, piperi- 
dine, atropine, etc., oxidize aloin solutions readily. 
From what has been said, it can be seen that there is a strong” 
similarity between the oxidizing action of wheat roots and catalyzers 
like inorganic salts and benzaldehyde and quinone. Probably the 
similarity is one of analogy only, the methods of oxidations being 
but different modes of oxygen transference to easily oxidizable 
bodies. ‘ 
Kastie and LoEvENHART (35) concluded that the so-called 
oxidizing ferment of the potato is not a true enzyme, but is an 
organic peroxide. They believe that the oxidation phenomena 
occurring in plants, and probably also in animals, can be satis- 
factorily explained upon the supposition that the readily autoxi- 
dizable substances which they contain are oxidized to the peroxide 
condition by molecular oxygen, and that the peroxides thus formed 
in turn give up part of their oxygen to other less oxidizable sub- 
stances present in the cell. In other words, the process of render- 
ing oxygen active by the living cell is probably brought about m 
essentially the same way that this is accomplished by phosphorus, 
benzaldehyde, and other oxygen carriers. : 
In regard to reduction by the living cell likewise, uncertainty 
exists as to whether it is brought about by a true enzyme OF by 
non-enzymotic bodies. HEFFTER (36) has given this question 
much attention and has come to the conclusion that the reducing 
activities of organisms are not due to enzymes. As in the case tv) 
oxidation, reduction processes comparable to those of the living 
root may be brought about by purely chemical means, as we have 
previously shown (2). 
As regards oxidation and reduction, it may be said that oxida- 
tive bodies may be extracted from the plant roots by suitable 
means. No body‘which would reduce sodium selenite in the cold 
could be extracted, however, although the water extracts of the 
seedlings reduce the selenite on heating. Thus it seems that the | 
reduction of the selenite by the wheat roots is due to the metabolic 
