50 The Potatoe Plague. 
nourishment; but this will not at all account for the decay of 
roots dug in an apparently healthy state, after being stored, 
Again, we have a goodly array of proofs that insects of dif- 
ferent kinds are found in the diseased potatoe, both in the 
tops and the tubers ; but it is by no means sure that they are 
the cause of the disease; on the contrary it seems highly 
probable that they are generated by it. This theory has, 
comparatively, few supporters, and does not seem to be con- 
sidered entitled to much consideration by the learned in such 
matters. 
A third theory, of which Doctor Hitchcock, of Amherst, is 
the most prominent supporter, attributes the universal sick- 
ness of the potatoe to “atmospheric agency, too subtle for the 
cognizance of our senses, like those which bring such epi- 
demics as the influenza and the cholera over particular dis- 
tricts or continents? Modern science,” he adds, “has shown 
us that many of the most powerful agencies of nature are 
concealed from common and even acute observation. May 
there not be others, yet undiscovered, which deeply affect the 
delicate machinery of organic life?” 
Aye, truly may there; and there may be a sixth sense, 
and a measure to infinity, and a limit to time and eternity. 
It is much easier to ask than to answer questions, and, when 
they relate to things confessedly beyond or above human 
intelligence, it is hardly worth while to ask them. ‘There 
may, nay, there must be a cause for the yellow fever, and the 
cholera, and the potatoe plague; but if it is not within the 
capacity of the senses, it is hardly worth while to grope for 
it. Ido not mean to undervalue inquiry, of any kind; but 
it seems to me that it is time enough to seek the transcenden- 
tal causes of an effect, when the visible, tangible, and palpable 
ones have been thoroughly examined. It is not proved, — 
there is no evidence beyond conjecture, that yellow fever or 
cholera is dependent or consequent on atmospheric agency ; 
