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 moie 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 fiom 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 diills quickly split, there would be little 
heard of the failure even in the dryest season. I own it is 
difficultto 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 twber 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 (18438,) 
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 
3 
