Diseases of the Potatoe. 25 



refer to the possibility of plants indicating constitutional 

 weakness, and why may not the potatoe ? I have all along 

 been of the opinion that the failure has arisen from this cause, 

 nor does it seem to me to be refuted by the fact, that certain 

 varieties of potatoe have been cultivated for many years in 

 the same locality without fail ; because it is well understood 

 that every variety of potatoe has not indicated failure, and 

 one locality may be more favorable to retention of vigor of 

 constitution than another; at least, we may easily believe 

 this. I have no doubt in my own mind that were seed pota- 

 toes securely pitted, until they were about to be planted, 

 not over-ripened before they were taken out of the ground, 

 the sets cut from the crispest tuber and from the waxy end ; 

 the dung fermented by a turning of the dung-hill in proper 

 time ; led out to the field, quickly spread, the sets as quickly 

 dropped in it, and the drills quickly split, there would be little 

 heard of the failure even in the dryest season. I own it is 

 difficult to prove the existence of constitutional weakness in 

 any given tuber, as its existence is only implied by the fact 

 of the failure ; but the hypothesis explains many more facts 

 than any other, than atmospheric influence, for example, 

 producing the failure like epidemic diseases in animals, for 

 such influences existed many years ago, as well as now. The 

 longer the cultivation of the tuber of the potatoe, which is not 

 its seed, is persevered in, the more certainly may we expect 

 to see its constitutional vigor weakened, in strict analogy to 

 other plants propagated by similar means ; such as the failure 

 of many varieties of the apple and pear, and of the cider 

 fruits of the seventeenth century. This very season (1843,) 

 contradicts the hypothesis of drought and heat as the primary 

 cause of failure, for it has hitherto (to June) been neither hot 

 nor dry, while it strikingly exemplifies the theory of consti- 

 tutional weakness, inasmuch as the fine season of 1842 had 

 so much over-ripened the potatoe, farmers still unaware of 

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