THE POTATO 133 



fact all the varieties in cultivation thirty years ago have 

 disappeared. Twenty-five to thirty years is therefore the 

 maximum duration of a variety. Owing to the special methods 

 of rapid propagation now adopted when good varieties have been 

 raised, the duration of life has been considerably shortened, and 

 about ten to fifteen years is the average duration of life of the 

 varieties now in use. The best " seed " Potatoes are found to 

 be medium sized tubers (what gardeners call the " big-little " ones) 

 with shallow " eyes " and smooth skins. Sometimes larger 

 tubers are cut into two or three pieces (each piece, of course, with 

 an " eye ") for planting ; but these do not give such good results, 

 probably because of the loss by evaporation of water across the 

 cut surface, which naturally hinders the growth of the shoot. 

 Numerous experiments in various parts of England have 

 demonstrated the fact that the largest yields are obtained from 

 seed procured either from Scotland or from Ireland. The 

 experiments conducted by the Lancashire County Council showed 

 an increase of from one to four tons per acre in the case of seed 

 obtained from Scotland, as compared with seed obtained from 

 the south of England. The seed Potatoes should be procured 

 early in the spring, and should be at once " boxed." That is to 

 say, they are placed in shallow boxes, each box containing one 

 layer of tubers, and kept in a shed or stable, where an even 

 temperature high enough to cause the tubers to sprout is 

 maintained. The sprouting must proceed in the light, so as to 

 produce short internodes, and must be so managed that short 

 internodes are developed at the time for planting. Stems with 

 long internodes have fewer points from which tuber-producing 

 stems can arise. All but the two strongest shoots should be rubbed 

 off just before planting. In the Lancashire experiments above 

 referred to, sprouted tubers gave an increased yield of nearly 

 two tons per acre over the unsprouted tubers. The best soil 

 for Potatoes is a deep, light loam, well drained, possessing a rich 

 store of well decayed organic matter. It is important that the 

 soil should be open enough to allow full expansion of the tubers. 

 Cold undrained clay and peat soils are the most unsuitable of all. 

 Potatoes of the best quality are not produced when the soil 

 contains much undecomposed farmyard manure, and hence the 



