46 The Potatoe Plague. 
whole family, however plausible or natural such deduction 
may be, is certainly not the way in which scientific knowledge 
has been brought to its present degree of perfection. Be- 
cause a certain mode of treatment has proved beneficial to a 
lymphatic inhabitant of the arctic circle, in a particular dis- 
ease, does it follow that the same mode would produce the 
same result on a sanguine or bilious temperament between the 
tropics? Does it follow that the same laws and government 
to which New England quietly submits would be fitting for 
the island of Hayti, or one of the pseudo South American 
Republics? Yet this is the process of reasoning and induc- 
tion that has been apphed almost universally to the culture of 
the potatoe. 
One writer has tried one or two varieties of the root in 
certain soils and situations; he has applied certain manures 
and a particular treatment of his own, and he therefore 
argues that what has suceceded or failed with his variety will 
be equally successful or otherwise, with the whole potatoe 
family. This is, to the multitude, very plausible and com- 
fortable doctrine; they adopt it, and suffer, because they 
have not discovered that the coat that fits a tall, thin man, 
will not fit a short, thick one, of equal weight. 
We sometimes find, in investigating the reports of scientific 
men, that the same variety, planted and dug at the same 
season, from the same soil, and having received the same 
treatment, in short, as far as human sagacity can discern, 
having had precisely the same advantages and disadvantages, 
has shown very different results. In one field, the crop is 
healthy and abundant; in another, it is scant, defective and 
diseased. The reader will find many instances of this kind 
by referring to the report of the Commissioner of Patents to 
the twenty-eighth Congress. "What, then, is the inference? 
Clearly that the disease is owing to some cause independent 
of culture, or soil, or weather, or atmospheric influence; that, 
