224 



U. SUZUKI. 



Summary and Conclusions. 



1) . The diseased leaves are remarkably poor in nitrogen 

 and the development of fibres is considerably retarded ; no other 

 peculiarity is regularly found. The shrinking of the leaves and 

 the retardation of growth may be due to the deficiency of 

 nitrogen and the bad development of fibres. 



The deficiency of nitrogen in the diseased plants is not 

 caused by an insufficient supply of nitrogen manures in the soil, 

 but must be due to a diminution of the absorptive power of the 

 roots, and also of chemical activity in the plant cells ; since the 

 disease is always observed in those places where soluble manure 

 is given in excess and over-growth is induced. Further, the 

 diseased plants can never recover on simple application of 

 nitrogen manures. 



The diminution of chemical activty in the living cells, owing 

 to the deficiency of nitrogen, may also be the cause of the bad 

 development of fibres, since the formation of cellulose from solu- 

 ble carbohydrates is performed by the living protoplasm. 



2) . During winter a considerable amount of reserve mate- 

 rials (especially nitrogen compounds and starch) is stored up in 

 the bark of stems and roots, and in spring, when the develop- 

 ment of new leaves commences, the greater part is transported 

 to the growing parts, and the assimilation products in the leaves 

 again come down in late autumn, when the leaves begin to fall. 

 Therefore the stems and roots are considerably poorer in reserve 

 materials during the growing season. Now it will be at once 

 evident that the cutting of the plants in the growing season must 

 have a very bad effect on the new developing shoots, since they 

 must be nourished with scanty reserve materials, and moreover, 

 it is not impossible that the reserve materials may be entirely ex- 

 hausted before the new shoots have attained a certain height and 

 become able to assimilate independently enough nutriments from 

 outside. In such a case the shoots will not grow normally and 

 the disease must be the result. Many facts support this 

 view : — 



a). The first appearance of the disease is always in the new 

 shoots, after cutting in the growing season. 



