1 66 The Ohio Naturalist. [Vol. XIII, No. 8, 



overproduction of oxidases in the varigated leaves. He says (1902, 

 p. 277). "The fomiation 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) confinned Woods' (1S99, 

 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 coinpounds. 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. Hcintzel (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 boihng 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 qviantities to regenerate practically 

 the original amount of active enz^one. 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 regtdate the 



