The Ohio Naturalist. 
[Vol. XIII, No. 8, 
166 
overproduction of oxidases in the varigated leaves. He says (1902, 
p. 277). “The formation of oxidases and peroxidases in abnormal 
quantities is a peculiar symptom of this disease and at the same 
time one notices that the translocation of starch and nitrogen 
compounds is noticeably delayed, so that appreciable quantities 
of starch are accumulated.” He (1902) confirmed Woods’ (1899, 
1902), experiment on the inhibiting effect of oxidases on diastatic 
action. Hunger (1903, 1905) and Shibata (1905) were not able, 
however, to confirm Woods’ work and Hunger criticises this 
theory, believing that Woods worked with impure enzyme solu¬ 
tions and that it was not the oxidase, but rather the tannin which 
interfered with the diastatic action. Woods (1899, p. 749), how¬ 
ever, had shown that diastatic action is hindered even if tannin 
is removed so that the retardation must be due to the oxidases 
present. He is not certain that the inhibiting action is as marked 
during warm weather and under natural conditions. One would 
naturally expect that such an interference would hinder the pro¬ 
duction of sugars and proteid compounds. It is on account of 
of this Woods (1902) believes, that cells of the diseased areas 
are very poor in reserve nitrogen. Suzuki’s (1902) chemical 
analysis shows this to be the case with the mulberry disease. 
Woods (1899, p. 750) finds that “peroxidase is always more 
than twice as strong in the light colored areas as in the green. ” 
In albino spots he found the oxidase twice as strong as in the green 
areas of the same leaf or in healthy leaves.” (p. 753). “It has 
been suggested by Dr. Loew that partial starvation may cause 
the increase of these enzymes in a cell, and it has been shown by 
Brown and Morris, that starvation causes an increase of diastase 
in the cells of various plants. ” These enzymes occur throughout 
the plant according to his statements and when diseased plants 
disintegrate the enzymes enter the soil and may later be taken up 
by other plants. Heintzel (1900) and others are also of the opinion 
that the disease may be disseminated in this way. 
Woods (1902) is not able to explain the infectious nature of 
this disease in accord with the facts, unless the oxidizing enzymes 
artificially introduced into the plant have the power of evolving 
these changes. He believes that a zymogen exists for these 
enzymes. By boiling juice from diseased plants he apparently 
destroyed the oxidizing enzymes which preliminary tests had 
shown to be present. After this same juice had been allowed to 
stand for a day, further tests gave a strong reaction for oxidases. 
A second boiling after four hours was not followed by a regener¬ 
ation of the enzymes. He concludes, therefore, that the zymogen 
exists in the cells in sufficient quantities to regenerate practically 
the original amount of active enzyme. He believes that as soon 
as the active enzyme is removed or destroyed, it is regenerated by 
the zymogen. The protoplasm is not supposed to regulate the 
