THE POTATO. 



281 



tato crop was so late that the frost came on and 

 blackened the leaves, while they and the stems 

 were still green, and the tubers of course not 

 ripe. The change of climate was therefore not 

 the sole cause of prevention, if indeed it was the 

 cause at all, for when the full ripened potatoes 

 were planted in the moors, the curl appeared in 

 them, in situations where there was none in the 

 native potatoes. It was thus found that the 

 curl could be prevented by using tubers that 

 were not quite ripe. 



A writer in the Gardener's Magazine for May 

 1827 thus ingeniously accounts for this fact: 

 " The potato tuber is a perfect organized sys- 

 tem, in which the circulation regularly proceeds, 

 and if suffered to ripen will then tend to decay ; 

 but if separated before ripe from the stem or 

 stalk which furnishes it with blood or fruit-sap, 

 descending from the leaves, the circulation of the 

 blood-sap is suddenly arrested. The ripe potato, 

 having performed all its operations, becomes 

 more inert ; but the circulation of the sap in the 

 unripe tuber having been stopped, it starts more 

 readily, and with greater vigour, when planted ; 

 the one appears to die, worn out with age, the 

 other seems accidentally to have fallen asleep, and 

 when awakened, possesses an unspent vigour and 

 energy." — p. 317. 



That over-ripeness is the principal cause of 

 the disease, has been found by experience to be 

 so much the case, that out of the same potato 

 it is possible to make some sets that will, and 

 others that will not, produce the curl. The por- 

 tion of the tuber that is nearest to the cord by 

 ■which it is fastened to the plant, ripens first, as 

 any one may observe, especially in an elongated 

 potato, where the root end is often so mealy as 

 to fall to powder, when the top or thick end is 

 soft and waxy. If such a potato be taken when 

 only the small end is ripe enough to boil mealy, 

 the eyes upon another of the same parcel that 

 are upon the waxy part, will all produce sound 

 plants, while curl may appear in those which 

 are taken fi-om the mealy end. The soil and 

 mode of culture may have likewise some effect 

 in producing this evil. Experience has shown 

 that high culture and stimulating manure tend 

 more to produce curl than poorer treatment; 

 that this disease is less frequent in new lands 

 than in those which have been long in culture ; 

 and that it seldom appears in cold and upland 

 places. 



The following facts, collected by the late Sir 

 J. Sinclair, on this important subject, deserve 

 attention. About the beginning of October, a 

 gentleman took his potatoes out of the ground, 

 put them upon some straw in a vault in the cel- 

 lar, and covered them with straw on the top, 

 v^liere they were left for the winter. It was im- 

 possible for frost to approach them. In the suc- 

 ceeding February a friend requested a few of 



them to plant. Accordingly, about a bushel 

 were taken from the store, and put in an out- 

 house in the yard, where they remained for some 

 time, during which there were several severe 

 frosts. It was evident that the frost had affected 

 them ; and the gentleman therefore detenuined 

 to try what effect it would have upon them. 

 They were planted; and the consequence was, 

 that one-half of them had curled leaves, and was 

 not half a crop. Those which remained in the 

 vault until they were planted were not in the 

 least disordered. Many other causes may doubt- 

 less produce this disorder ; but the foregoing ex- 

 periment clearly demonstrates, that frost mil 

 cause it, and ought therefore to be most carefully 

 guarded against. 



There is reason also to believe, that the fre- 

 quent application of lime to the soil will occa- 

 sion this disease, of which the following experi- 

 ments furnish a strong proof; A piece of gi'ound 

 (deep loam) was well manured with lime, and 

 planted with potatoes. When the plants ap- 

 peared above ground, nearly thi-ee-foui'ths of 

 them were curled ; while at the same time a few 

 drills, immediately adjoining, which had got no 

 lime upon the soil, and planted with the same 

 seed, were entirely free from the distemper. This 

 cii'cumstance attracted notice, and the same ex- 

 periment was repeated next year, with the same 

 result. 



Any cause that weakens the plant must cer- 

 tainly occasion the curl ; but there is nothing to 

 which it can be more justly attributed than to 

 the sets lying in heaps in a house, and being suf- 

 fered to heat before they are planted. On the 

 other hand it has been remarked, that when po- 

 tatoes, to be used as seed, are kept in pits under 

 ground, and not in a house, the crop is seldom 

 liable to that distemper. 



The best means of avoiding the cuvl is, to 

 change the seed every second or third year, as 

 from moss land to cultivated soil, and vice versa. 

 It is a practice of the Lancashire planters to send 

 some of their favourite kinds to the mossy 

 grounds to recover, if they are found to have 

 a tendency to curl ; and it is certain that pota- 

 toes from mossy lands will not curl. The moor 

 lands in Yorkshire, and the mountains of Rad- 

 nor and Montgomery, are free from curl, while 

 the vales are infested with it. 



It has also been found, that sets taken from 

 young potatoes are not so liable to the curl as 

 those which have been forced to a great size by 

 rich manui-e and earthing up ; and some farmers 

 on purpose sow the potatoes intended for seed 

 later than the rest, that they may not attain 

 great size or maturity. 



The economy of this article of food, as com- 

 pared with wheat, is seldom questioned, although 

 doubts have been raised even as to its compara- 

 tive cheapness with wheaten bread. The fol- 

 2n 



