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no more apprehension in regard to the extinction of species, whether of 
plants or animals, than we have of the sky’s falling, or of the earth’s 
being brushed out of existence by the tail of the next comet. We may 
theorize upon the matter, and build up elaborate propositions against the 
productive power of nature, but the next year’s growth of the potato 
will be much more likely to topple down all our theories than to estabish 
any legitimate conection with them and the first physiological fact. 
We are not inclined to speak lightly of this ‘wearing-out’ hypothesis. 
We believe it to be false,-but are willing its advocates should attach any 
and all the weight they wish to its hypothetical data. Whatever may be 
its merits as a theory, it is absolutely incapable of verification by facts. 
There can be no experience argument in the case; and a hypothesis with¬ 
out being supported by experience, or scientific evidence of some kind, 
is at best a mere dream—a piece of idle and vagrant fancy. 
We propose, however, to comply with the demands of this hypothesis 
for facts, to see whether such as we have, verify or contravene the several 
propositions it necessarily involves. 
And first, the general diffusion and simultaneous appearance of the 
disease over extensive regions of country, is a fact wholly irreconcilable 
with the theory of gradual exhaustion. The malady everywhere appears 
like a broad-spread epidemic. The plant instead of being exhausted by 
age seems suddenly to have contracted a malignant and fatal disease, from 
which no variety appears to have wholly escaped. Even the seedling 
varieties, those recently produced from the ball, have not escaped the 
general contagion. The Bogota seedlings, raised from the seed-balls of 
the native potato, have exhibited indications of the disease. The same is 
true of the Chili seedlings. 
Another fact, not only inconsistent with the theory of exhausted vital¬ 
ity, as the remote cause of the disease, but also of the sudden alterations 
of the weather at critical periods in the growth of the plant, as the prox¬ 
imate cause, is the appearance of the disease at Bogota, in New Grenada, 
in Peru, and other parts of South America, where the plant grows in¬ 
digenously. 
And another fact, wholly irreconcilable with the theory, is, that potatoes 
taken from the Atlantic States to California are restored to their accustom- 
