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When young tubers are checked, ripen prematurely and are harvested, 

 the eyes have not developed normally. Shoots developing from these eyes 

 must naturally be weak. If such tubers are used the following year as seed 



Fig. 16. 



The basal portion of a cutting- grown in water from a potato tuber with 

 the filament disease (natural size). (Orig-.) 



for similar cultivation, these phenomena of weakness must gradually in- 

 crease and result finally in the growth of thread-like stems only. According- 

 ly the disease is the result of a continued unwise cultural method ; viz., an 



