CHAPTER XIV 



THE OXIDASES IN RELATION TO PLANT PATHOLOGY 

 AND TO TECHNOLOGY. 



SECTION I. PLANT PATHOLOGY 



DISEASE OF THE MULBERRY LEAF. 



SINCE upon the death of the protoplasm oxidases act 

 without the restraints to which they are subjected during 

 its life, it might well be supposed that conditions un- 

 favourable to the normal metabolism of the cell might re- 

 sult in increased oxidase activity. This has been found 

 true in a number of instances. For example, it had been 

 observed that when mulberry- trees were cut back too 

 frequently, an abnormal yellow colour and crinkled appear- 

 ance resulted in the leaves. Suzuki (1900), investigating 

 this, found that an excessive production of oxidases had 

 taken place in such areas. He attributed this to the lack 

 of proper nutrition of the rapidly growing tissues. 



THE MOSAIC DISEASE OF TOBACCO PLANTS AND 



THE POTATO LEAF-ROLL DISEASE. 

 Much the same phenomena were observed by Woods 

 (1902) in the " mosaic disease " of tobacco plants which 

 had been cut back. He also demonstrated that the 

 condition was rendered more acute by the application 

 of certain manures which increase the rate of growth, 

 and adduced reasons for the belief that the excess of 



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