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habit, caused him to leave those sets upon a barn floor, drying 
for more than a week. He planted with them a two-acre field, 
and not more than three-fifths vegetated ; of which three-fifths 
a fourth was in various degrees curled. Similar results were 
obtained in the experiments of a market gardener When the 
sets were allowed to ferment in a heap, allowed to sprout, &c., 
he had a crop one-fifth of which was curled. Every one 
acquainted with the cultivation of the potato, is aware of the 
great difference existing in the varieties as to their early and 
rapid vegetation ; those that excel in this quality are, of course, 
the most easily excitable. A consequence of this is, that they 
are always planted earliest in the spring, before their vital power 
has become very active ; and of all crops, practice demonstrates 
that these early ones are least liable to the curl. But what is 
the consequence on the contrary, if an early variety is planted 
for a main crop later in the spring, when extraordinary pains 
in keeping them cold and dry have not been employed to check 
their vegetation, and consequent decrease of vital energy ? 
Such crop then is, more than any other, liable to the disease ; 
and a good preventive has been suggested by Dr. Bindley, 
namely, that of planting the tubers in autumn, immediately 
after they have ripened.” 
“The results of my view of the disease, sustained by numerous 
experiments, are that it will never occur if the following points 
are attended to : — First, that the sets are from tubers that exhibit 
scarcely any symptoms of incipient vegetation. To effect which, 
they ought throughout the winter, to be preserved as cool, and 
as much excluded from the air as possible. Secondly, that the 
tubers should be perfectly ripened. Thirdly, that they should be 
planted immediately after they are cut. Fourthly, that the 
manure applied should be spread regularly, and mixed with the 
soil, and not along a trench in immediate contact with the sets. 
Fifthly, that the crop is not raised, for several succesive years, 
on the same area.” 
In the extract we have here given, 3Ir. Johnson has well and 
practically borne out his theory. The subject is one we confess 
never to have investigated, perhaps on account of never having 
had potato crops affected by the disease in question. It may be 
that the practice we pursue of planting fair-sized whole potatoes, 
in rows a yard apart, affords protection from the disease, and 
