270 



U. SUZUKI. 



enzymes. Brown and Morris 1 proved that the secretion of 

 diastase is much enhanced by partial starvation. Weak lily 

 plants containing much of oxidizing enzymes, especially 

 peroxidase, are always those which have a very poor root 

 system and are suffering from partial starvation. Church ana- 

 lyzed the albino leaves of Ifex aqiiifolium. Hedera helix and 

 Acer negundo and always found less organic matter, especially 

 nitrogen compounds. Thus in Acer ii&gitndo the following 

 differences were observed : — 



Albino leaves. Green leaves. 



Water. 82.83 72.70 



Organic substances. 15.15 24.22 

 Ash. 2.02 • 3.08 



By the puncture of aphides, scale insects, leaf hoppers, 

 etc., the attacked parts show partial starvation, sugar and 

 nitrogenous matter being removed, and thus, as Woods found 

 again, an increase of oxidizing enzymes results. In short, there 

 is no doubt that the oxidizing enzymes stand in close relation 

 with many diseases of plants. This has led me to examine 

 whether in the mulberry dwarf disease, these enzymes are 

 also produced in abnormal quantities and stand in causal 

 relation to it. This will prove of interest not only for further 

 explanations of the phenomena of the mulberry dwarf disease, 

 but also as a further contribution to the knowledge of the 

 oxidizing enzymes. 



The tests for oxidizing enzymes in. the mulberry plant 

 were made exactly after Loew and Woods. The details are 

 as follows : 



a) Oxidase. 



Oct. 2. Several samples were gathered at Komaba, and 

 tested in the fresh as well as in the air dry condition. The 

 diseased leaves contained always more oxidase, sometimes 

 four or five times as much as the healthy ones. The air dry and 

 powdered leaves were at first treated with alcohol and ether, 

 the residue dried, ground in a mortar, and made into a fine 

 paste, with addition of some water. The paste was then diluted 

 and filtered, and to the clear filtrate were added a few drops 

 of guaiac tincture. A difference was at once observed between 



1 Journal of the Chemical Society Vol. XIII. London 1893. 



