ROOT CROPS. 219 



tuber softo'r and more spongy — and hence more subject to 

 decay ; more likely to be affected by unfavorable atmosplieric 

 conditions. And when this course of unnatural treatment is 

 continued for two centuries, it is not strange that, although the 

 amount of yield is increased, it may be done by undermining 

 the health, and perhaps diminishing the vitality of the plant. 

 Probably nature has limits beyond which her perversion cannot 

 be carried with impunity. 



Besides, in its wild state, the potato propagates itself by- 

 seeds as well as b}^ tubers. From recently grown seeds, it 

 annually renews its youth and health. And wild plants, which 

 reproduce themselves without human aid, resist tendencies to 

 disease better than cultivated ones. But we have checked the 

 potato in its habit of reproduction from seed, because we 

 wanted an increased yield of tubers — a result attainable, in 

 part, by preventing the plant from following out its natural 

 tendency to produce seed. We gain in one direction, and lose 

 in another. 



It has often been suggested, that we might, perhaps, recruit 

 the failing health of the potato, by raising it from seed ; and 

 experience teaches us, that potatoes so raised are usually best 

 for the table. But seedlings rot as much as potatoes raised 

 from tubers. Why not? They come from the seed of diseased 

 tubers. The seed partakes of the general deterioration. 

 Whatever may have been the primary cause of the disease, it 

 has infected the whole plant. And raising from seed neither 

 invigorates the vegetative principle, nor checks the tendency to 

 decay. There is a defective constitution, the vitality of which 

 cannot be so restored. The disease is a constitutional debility, 

 resulting from the unnatural circumstances in which the potato 

 is placed, analogous to readily acknowledged causes of decay 

 in other plants. Some kinds do not rot much; others are 

 almost destroyed; and all kinds arc more or less affected. 

 Some may have been cultivated for a shorter time than others, 

 and now have a sounder health. We may also be ignorant of 

 some conditions, which, besides long-continued and unnatural 

 cultivation, may be requisite to produce the result. Where it 

 is so difficult to pronounce positively upon the primary cause 

 of the disease, may we not be justified, in the absence of 



