The Potatoe Plague. 65 
failure in the potatoe crop,” says Mr. Thompson, “I paid 
more than ordinary attention to the selection of seed, and in 
1840 planted sixteen acres with potatoes, making choice of 
two kinds of round red varieties, both of them new to my land. 
The gentleman from whom I obtained them, having two farms, 
one of stiff, the other of light land,—had changed his sets 
regularly from one to the other. J planted them on a sandy 
Joam, which was in a high state of cultivation, and my reason 
for planting it with potatoes was solely because I was aware 
if sown with corn it would be so lodged as to be nearly 
worthless. They were planted in the last week in April. I 
naturally expected a heavy crop, but was much disappointed, 
as symptoms of curl soon appeared. This increased, and 
though few of the plants perished, nearly the whole were 
unhealthy. Iwas so much surprised at the appearance of 
curl that I watched and examined the plants at several 
periods of their growth, taking up roots here and there 
wherever I observed one either better or worse than its 
neighbors. The appearance of all those affected was nearly 
the same. The set, as long as the weather was dry, crum- 
bled and perished,—the disease seeming to proceed from 
certain spots or pits as centres, and gradually destroying the 
whole set. The cut sets were the worst, and the decay 
always commenced from the cut side of the set, but the 
whole ones also suffered. 
As soon as the weather became wet, these appearances 
changed, and the diseased portion of the set resembled a 
sponge, which after a short time became black and offensive. 
The effect on the plant was well marked. Wherever the 
disease had made a decided impression on the set, the stalks 
of the plant were marked with brown streaks and patches, 
and evidently showed that the juices which they were con- 
ducting from the set were vitiated and noxious. The part 
of the stalk to which I directed my attention was that under- 
6* 
