I/O 



U. SUZUKI. 



localities where, owing to deep snow and economical circumstanc- 

 es, the old custom of leaving the plants to their natural growth 

 is still adhered to, the disease is entirely unknown. This fact 

 deserves especial emphasis, as having a close bearing on the 

 true cause of the disease. Further, it deserves mention here 

 that although if the shoots are cut in spring before the expansion 

 of the leaves or in autumn after the fall of the leaves, the 

 plants remain perfectly healthy, yet if the cutting takes place in 

 the period of luxuriant growth, and especially in the so-called 

 " late cutting " (i.e. in the latter part of July or in August), they 

 are particularly liable to attack. 



9 



The first sign of the disease usually appears on new shoots 

 springing from the stump. Namely, when these have reached 

 the height of one foot or so the upper leaves either begin to 

 shrivel or manifest other signs of debility, and as the shoots 

 continue to lengthen, all the new leaves developed from them 

 betray the same character. The diseased leaves may turn yel- 

 lowish or remain dirty green, or may be indistinguishable in 

 color from the healthy leaves, merely shrivelling up. In acute 

 cases the leaves may all shrivel up in one year, but more usually 

 only a few leaves near the top of the shoots first betray their 

 debility, whence the disease spreads with each successive cutt- 

 ing, until in the course of a few years the entire plant is attacked 

 or even dies off. The branches of the attacked plants remain 

 usually slender, and the twigs and leaves are very numerous. 

 Sometimes also, the branches lose their strength and become 

 procumbent. In fact the diagnosis is somewhat variable, some- 

 times consisting in the paucity of the sap, as if the plants were 

 grown in dry soils, or sometimes in the arrest of growth, as if the 

 plants were still young ; but the unfailing signs are the imperfect 

 development and shrivelling of the leaves and the slenderness 

 and dwarfed condition of the branches. Moreover, when a plant 

 is once attacked recovery is possible only after two or three years 

 of complete protection from the cutting. 



Parasites have been hunted for in the leaves and branches 

 of the diseased plants, but none have been found that can be 

 regarded as having a causal connection with the disease. The 

 roots of the diseased plants are usually in a decayed condition, 

 and in more advanced cases even roots of a finger's thickness are 

 completely rotten ; and hence this decay of the roots has been 



