214 AGRICULTURAL TEXT-BOOK. 



ducts, and finally to grass, for cattle raising, for the use of distant 

 communities. But as the grass-product becomes genera] the population 

 gradually dccrekses in numbers. 



467. We shall not attempt to explain the cause of the Rot, 

 nor yet repeat the various theories which have been originated. 

 The ablest scientific men while each has his own private opin 

 ion acknowledge their inability, satisfactorily to account for it, 

 any further than for the cholera and similar human epidemics. 

 It is probably owing to some undetected atmospheric influence, 

 and may be connected with electrical phenomena. One fact, 

 however, appears to be generally acknowledged, viz, that rich, 

 ammoniacal fermenting manures^tend to increase tho disease, and 

 that new soils, of a porous character, or old soils supplied with 

 inorganic manures, are apt to produce the healthiest tubers. It 

 is a peculiarity in this case, that remedies which are successful 

 in one instance or locality, entirely fail in others; and thus, all 

 specific curative means are now looked upon with suspicion. In 

 Russia, drying the potato soon after digging, by artificial heat, 

 has been found successful, yet failed in England; while, in 

 Michigan, Mr. Mott and others have remedied the evil by leav 

 ing the tubers intended for seed in the ground where they grew 

 until required for planting, taking the precaution to plant deep 

 and cover with straw to prevent freezing. It is certain that in 

 some soils this is a perfect preventive, and some unexplained 

 change goes on in the potato ; for, in the second season, the old 

 potato which has acted as seed will be found perfectly sound, 

 hut altered in flavor. The same gentleman recommends leav 

 ing the tubers, intended for eating in the spring, in the ground 

 all winter, when they will bo found as fresh and unaltered as 

 they were in the preceding autumn. (See Farmer s Compan 

 ion and Horticultural Gazette, Vol. i, p. 77. ii, p. 14 .) The fol 

 lowing receipt has been lately published by an English farmer, 

 not only as a manure, for which purpose it is undoubtedly excel 

 lent, but also as a preventive : (Agricultural Gazette.) 



