66 The Potatoe Plague. 
ground, in which it was easy to trace the progress of the 
disease, from their being white and nearly transparent. 
Wherever the stalk was curled, I found the sets diseased. In 
some cases the disease carried the day, and the set reaching 
an advanced stage of decomposition, and the stalks below 
ground becoming quite brown, the tops died away. In a 
subsequent season (1844) most of the sets attacked perished ; 
but on this occasion a great majority of the plants threw 
out strong roots, and finding an abundant supply of food, 
maintained a constant struggle with the disease, and event- 
ually yielded a good half crop. 
The experience of this season convinced me that curl, dry 
rot and wet rot, are one and the same complaint; that eurl is 
a mild attack of the disease, which, when violent, destroys 
the set before it can germinate ; and that it assumes the form 
of dry or wet rot according to the degree of moisture of the 
goil or season. J have repeatedly seen potatoes affected with 
dry rot, in a few days assume appearances by which wet rot 
is usually described; and this change was evidently attrib- 
utable to heavy rains which had fallen in the interval. 
1841. As I still considered the red potatoes above-men- 
tioned to be good kinds, and that the occurrence of curl was 
accidental, I determined to give one of them another trial; 
and accordingly, I planted about an acre and a half with sets 
from the crop of 1840, which had suffered so much from curl. 
They were planted as Jate as the 8th of June, the weather 
dry and unfavorable ; yet in spite of these disadvantages they 
came up well, grew luxuriantly, and produced an excellent 
crop. Side by side with these potatoes two other kinds were 
grown; one a black kidney, a very superior potatoe for the 
table, the other a cattle potatoe. These were bought sets, 
nor do I know how they had been previously treated. Both, 
however, were failing crops. The experience of this year 
was valuable, running directly counter to what has been so 
