MULBERRY-DWARF TROUBLES IN JAPAN. 279 



the extract was boiled before the addition of starch paste no 

 reducing sugar was produced. The presence of the diastatic 

 ferment was beyond doubt. 



Oct. 12. Akagi (cut in autumn) at Nishigahara. The root 

 bark of both, healthy and diseased plant, contained originally 

 some reducing sugar. That of the healthy one however con- 

 tained considerably more diastase than that of the diseased. 



Oct. 12. Takasuke at Nishigahara (cut twice in a year and 

 deprived of the young leaves and hence diseased). The root 

 bark, of both, the healthy and diseased plants contained very 

 little diastase. 



Oct. 12. Akagi (cut in summer) at Nishigahara. The root 

 bark, both of the healthy and diseased plants contained little 

 diastase. We see from the above experiments that the diseased 

 leaves contain generally more of diastatic ferment than the 

 healthy ones, but no distinct relation was observed with the 

 root bark. 1 



Woods has observed that oxidase can inhibit the action 

 of diastase ; This depends of course much upon the relative 

 quantities of oxidase and diastase. In the cases above described 

 the oxidase was probably too diluted to prevent entirely the 

 diastatic action. 



On the existence of catatase in the mulberry leaves. 



Catalase was found by O. Loevv in 1900 in the leaves of 

 the tobacco plant ; He first observed that the tobacco leaves 

 contain an insoluble enzym which liberates oxygen gas from hy- 

 drogen peroxid. Physiologists have until now attributed this 

 action on hydrogen peroxid to every enzym. Loew confirmed by 

 careful investigation the different and independent nature of the 

 enzym and proved that diastase or any other enzym in their purest 

 state never possess this property. He extended his observation 

 to several other plants and at last reached the conclusion that 

 the enzym is contained in every living cell of plants. It has 

 decidedly the important function to destroy every trace of the 



1 The apparent contradiction between the existence of diastase and that of much 

 starch in the diseased leaves is easily explained on the ground that the sugar formed 

 by diastatic action is not transported to the trunk and hence that it is always reconverted 

 into starch by the cbloroplasts. We further have to concede that there may be in the 

 diseased leaves, as long as they are fresh, only the zymogen of diastase, which in my 

 experiments just mentioned, generally was transformed into diastase itself. 



