On the Prevention of Curl and Dry -Rot in Potatoes. 167 
of Sawdon has been a potato-grower for more than thirty years ; 
used formerly to send 500 or 600 bushels of Sawdon kidneys 
annually to Selby, where they were used for seed, and the pro- 
duce sent to London; used to grow as many as 200 bushels to 
the acre, now considers 50 bushels a good crop ; has failed so re- 
peatedly in the last five years in growing a crop that this year 
(1844) he has none ; believes there is no one in the township who 
continues to grow the kidneys except one old man of the name 
of H. The township of Sawdon has been enclosed, planted, and 
other improvements made, within his recollection. H. of Sawdon 
Moor has occupied a few acres of land reclaimed from the moor 
for twenty-two years, and has grown Sawdon kidneys the whole 
time, and always in the same field! Only about one-third of it, 
however, is in potatoes at once. My informant adds that H. 
considers his potatoes are ripe when he takes them up, but he 
(informant) does not consider them as ripe as his neighbours ; 
and when the elevation, exposure, and cold wet nature of the soil 
that he farms, are taken into account, it seems probable that his 
potatoes are seldom if ever thoroughly ripened. In the case of 
Sawdon we have no direct evidence that the failure of the once 
famous Sawdon kidneys is to be attributed to over-ripening of 
their seed-potatoes, but the probabilities are strongly in favour of 
this supposition. In the first place, the potato itself, like all the 
kidneys, rij)ens early ; and in ordinary situations would, if taken 
up at the usual time of potato-harvest, be too ripe to make good 
seed, and this is now found to be the case at Sawdon, and its 
growth is abandoned ; but in former years, when the township 
(which borders on the moorlands, and partly consists of what 
farmers there call " wet clayey gravel," partly of black peaty soil) 
was unenclosed, undrained, and without shelter, the climate was 
sufficiently backward to make the "kidneys" immature when 
taken up, and consequently to be held in high repute, and sent to 
great distances for seed. It may be urged that ■ the failure may 
with equal probability be attributed to the gradual deterioration of 
this species of potato ; and to meet such an objection I have in- 
serted the case of H. mentioned above, who still grows, with 
profit to himself and advantage to his neighbours, the identical 
species supposed to be worn out, and moreover has grown it every 
third year on the same soil for twenty-two years, and in the same 
township where it had been previously grown time out of mind. 
I will now state the chemical facts which appear to me to con- 
firm and explain the above-mentioned results of practice. It is 
notorious to potato-growers that a marked change takes place in 
the quality of the tuber when the stem and leaves wither, and 
that potatoes taken up when the plant is still growing are invari- 
ably watery, though a portion of the same plot, if of a good sort 
