48 The Potatoe Plague. 
I have said that many theories have been broached in 
regard to the supposed potatoe epidemic. Most of them are 
entitled to respect, as the results of the laborious investiga- 
tions of ingenious, learned, or practical men; and I shall 
therefore briefly notice a few of them, with such comments 
as they appear to me to require. 
The first of these theories attributes the rot to too early or 
too late planting and digging. There is no doubt, in my 
mind, that either of these causes will injuriously affect a crop ; 
the failure on a field, or a farm, may justly be referred to 
either or both of them. It needs no ghost to tell me that 
green fruit is unwholesome, or that, if allowed to hang too 
long on the tree, it will rot; but these causes are altogether 
insufficient to account for a decay extending over all christen- 
dom, of many years duration, and of continually increasing 
progress. It cannot be that all, or even a great portion of 
those interested in the cultivation of the potatoe throughout 
the world, plant too late or too early, or fail to gather and 
store the harvest in its season. ‘This theory will do, there- 
fore, for a district, but not for the whole temperate zone. 
The same reasoning will hold good of the effects of soils, 
manures, and seasons. These have their influences; they 
are partial and local; but any considerable and general fail- 
ure may be prevented by care. It is hardly credible that 
they, or any of them, should, for a long series of years, exert 
the same baleful influence, every where. Besides, if this 
were the case, would this influence be confined to the potatoe 
alone, of all the vegetable kingdom? Do we hear of any. 
epidemic or general disease of any other vegetable? We do, 
indeed, hear, now and then, of a failure of the beet crop, or 
the crop of apples, here and there; but the next year makes’ 
all right again, and if fruit fails in New England, we get it 
from New York and Jersey. The world is not an Egypt, 
