MULBERRY-DWARF TROUBLES IN JAPAN. 



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the healthy and diseased leaves, thus the filtrate obtained from 

 the latter producing' at once a dark blue color, while in the 

 filtrate obtained from the healthy leaves the coloration set in 

 much more slowly and increased but gradually. 



2. Oct. 29. Roso variety, gathered at Komaba. The 



diseased leaves contained nearly two and a half times as much 

 oxidase as the healthy ones. As the leaves were still healthy 

 and the assimilation process was still energetically going on 

 and as there was no noticeable quantity of tannin and albumin, 

 the colorimetric comparison must be considered reliable. It is 

 also to be noticed here that the diseased leaves turned very 

 quickly reddish brown on being ground in a mortar with addition 

 of some water, chlorophyll and other organic substances being 

 changed in but a few minutes, whilejn the case of the healthy 

 leaves, the change of color was very gradual, the green color 

 of chlorophyll being retained for a longtime. This evidently 

 shows the strong oxidizing power of the diseased leaves. It 

 was generally observed that the growing leaves in full activity 

 and full assimilation energy, contained always less oxidase 

 than the old leaves. Very young plants, however, contained 

 sometimes much more oxidase than the full grown ones. So it 

 is very probable that the activity of oxidizing enzymes is 

 inversely proportional to the energy of assimilation. 



3. Oct. 5. /i/^vz^'-variety at Nishigahara. The diseased 

 leaves contained much oxidase but the difference from the 

 healthy ones was not so marked here. 



4. Oct. 27. Other varieties behaved as follows : 



Ycijiwase Diseased leaves contained 2-3 times as much oxidase. 



Ichihei „ ., „ 6-7 „ 



R °so „ „ „ 2-25 „ „ 



Tsurata ,, „ „ a little more but the difference not very marked. 



Nezumigayeshi „ „ „ 2 „ „ 



Shimanouchi ,, „ 2 „ „ 



Jumonji .. „ „ 2 



Akagi „ „ n a little more but the difference not very marked. 



Yanagita „ „ „ difference not very marked. 



Takasuke „ ,, ,, difference not very marked. 



Sometimes the difference was not very marked since the 

 extract was too concentrated, but after a proper dilution, the 



