Observations on the Mulberry Dwarf Troubles 

 (Schrumpfkrankheit), a Disease 

 Widely Spread in Japan. 



BY 



U. Suzuki. 



In a former No. of these Bulletins (vol. IV., No. 4) I report- 

 ed on the relations of the oxidising enzymes in healthy and 

 diseased mulberry leaves. In that article I mentioned however 

 only observations on leaves gathered in the late autumn, while 

 here I will report on analogous observations with leaves 

 gathered in the spring and summer. 



Besides the usual tests with guaiac resin, I also made tests 

 with guaiacol and hydrogen peroxid, whereby a red coloration 

 is produced. Various vegetable objects yield this reaction, 

 which I have also observed with mulberry leaves. Animal 

 objects give this reaction also, which is of special interest in the 

 case of the saliva, since this often fails to give any other oxidase 

 reaction, and probably contains a special oxidase. This can 

 however not be taken for granted in the case of plants, where 

 the blue reaction for peroxidase with guaiac tincture and hydro- 

 gen peroxid shows a striking parallelism to the red reaction with 

 guaiacol and hydrogen peroxid. Thus far I have not succeeded 

 in finding any vegetable object that yields one of these two 

 reactions alone. 



I have made numerous colorimetric comparisons with heal- 

 thy and diseased mulberry leaves in the manner described in my 

 former article (1. a), in regard to oxidase, peroxidase and the 

 guaiacol reaction, further comparative tests in regard to catalase, 

 0.5 g. of the fresh leaves serving for the test with 10 c.c. neutral- 

 ized hydrogen peroxid of nearly 2%. The volume of oxygen 

 developed in twenty-five minutes, shaking the mixture before 

 the final reading, ranged from 7 to 42 cc. 



