2S6 



U. SUZUKI. 



the development of the entire root system, finally causing its 

 starvation and death, the death being- followed by decay which 

 spreads "gradually into the larger roots. I have observed very 

 remarkable cases which furnish a convincing proof. The rows 

 of a mulberry plantation were alternately cut at the beginning 

 of June ; a remarkable difference was here already observed at 

 the end of July when the roots were examined. The normal 

 plants had white rootlets like net works while the plants of the 

 cut rows had no white rootlets whatever. Also the thickness 

 of the root bark showed a considerable difference. Thus it is 

 very evident that the power of developing new rootlets is more 

 and more retarded in consequence of the successive cuttings in 

 the growing season. 



On the quantity of reserve starch. 



I have already shown by careful analysis that the diseased 

 leaves and stems contain always less nitrogen, and Miyoshi has 

 also proved that the diseased stems and buds contain consider- 

 ably less starch than the healthy ones. As the migration of 

 starch and nitrogenous compounds from the diseased leaves is but 

 very slow, these phenomena are naturally to be expected. But 

 according to my assumption, the deficiency of reserve materials 

 is not only the effect of the disease, but it must become the 

 cause of its further development In other words, those plants 

 which had used up the reserve materials must first show the 

 disease. The following observations were made to test this view. 



1) . Jumonji, Sept. 30. The root bark of the healthy 

 plants contained much starch but that of the diseased contained 

 none. 



2) . Akagi, Sept. 30. The root bark of healthy plant 

 contained some starch, but that of the diseased not. As this 

 plant was cut at the end of August and the new shoots were 

 still very young, no new rootlets had yet developed. Sufficient 

 time has not yet elapsed for the new shoots to prepare the 

 reserve starch, on the contrary they were still depending upon 

 the reserve materials which had been prepared before cutting. 

 We can say that the first appearance of the disease is caused by 

 the exhaustion of the reserve materials in the roots. 



3) . Agaki (cut in autumn) was examined on Oct. 20, the 



