691 



and it is absolutely unknown in regions where the plants, under the old 

 cultural method, have not been cut at all. Consequently, we may maintain 

 with certainty that a phenomenon resulting from intensive cultivation is 

 concerned here. The fact that the plants remain healthy, which were cut 

 back in autumn or the early spring before the opening of the leaves, favors 

 the theor}^ that thi's cutting during the time of making growth is the cause 

 of the shrivelling disease. Diseased plants can be cured if left unpruned 

 for several years. 



The first indication of the disease appears generally when the young 

 branches, breaking out from the stump of the trunk, have reached a height 

 of one foot. First of all, the uppermost surfaces shrivel or show other 

 phenomena of weakness. This change advances gradually dovvnward, 

 while the leaves turn yellowish or dark green, or even can retain their 

 normal color. This usually sets in slowly since, in the first year, only the 

 upper leaves of some shoots become diseased. In the course of time, the 

 condition so spreads that the tree dies. There are, however, also acute 

 cases in which all the leaves shrivel at the same time in one year. The 

 branches of the diseased plants are usually very thin and develop very 

 numerous side branches and leaves ; they droop at times and lose their stiff- 

 ness. The roots begin to decay. 



Naturally, parasites have often been held responsible for this disease 

 and the phenomenon has been declared to be the result of a parasitic decay 

 of the roots but the roots are demonstrably healthy in the first stages of the 

 disease of the aerial parts ; besides this, it seems very remarkable that a 

 parasite always seeks only the trees treated with the pruning method. 



With due consideration of the preceding facts, one is forced to the con- 

 clusion that a continued disturbance of equilibrium in the nutritive processes 

 must be the cause here. This is confirmed by Suzuki's numerous analyses. 

 He found, for example, in the average from ten experiments that in leaves 

 of plants suffering from the shrivelling disease, when the content of the 

 healthy leaves is set at 100, the water content is 94.7 per cent. ; the dry 

 substance 116 per cent. In 100 parts dry substance the content is : — 



(normally valued at 100) 



Protein Si. 8 per cent. 



Fat 86 



Raw fibre 81.4 " 



Extractive substances free from nitrogen 120 " 



Pure ash 91 " 



Total nitrogen 81.8 " 



Albuminoid nitrogen 86.8 " 



Non-albuminoid nitrogen 66.6 



In 100 parts ash content. 



(normally valued at 100) 



Si Oo I ^3-1 per cent. K, O 92.3 per cent. 



SO 97.2 " CaO 105.5 " 



P.O. 101.6 " MgO 120.6 " 



