POTATO DISEASE. 283 



express the idea, of luxurious habits continued through many 

 generations. In this way the plant has acquired a predispo- 

 sition to disease, which is increased by high culture, and may 

 be diminished by culturc'of an opposite character. To prove his 

 position, he states that the disease shows itself in a more 

 aggravated form, in proportion as the crop is highly composted, 

 accompanied with a moist soil and atmosphere, and other 

 conditions favorable to the luxuriant growth of the plant. 

 These circumstances he supposes to be productive of a super- 

 fluity of water in the sap-vessels of the plant, thereby giving 

 origin to the disease. Hence the disease commonly shows itself 

 in the stalk before it affects the tuber ; and the fungal growth 

 which ensues, is the consequence of the corruption of the tuber. 



The same injurious effects, I would add, are well known to 

 follow long continued high manuring, both of fruit and forest 

 trees, especially in the early stages of their growth ; and there 

 is probably a, limit in all natural productions, both of the 

 vegetable and animal kingdom, beyond which " improvement" 

 suddenly stops, and degeneracy ensues. Hence the " running 

 out" of established varieties of artificial fruits, and of 

 improved breeds of domestic animals, which must occasionally 

 be crossed with a less improved stock, to restore their vigor of 

 constitution. As a remedy for the potato di*ase, Mr. Pritz 

 recommends that the tubers be planted in a soil which is well 

 drained, and in which the fertilizing materials have been 

 thoroughly mixed with the soil during the previous season ; 

 and he prefers a virgin soil to one made equally rich by artifi- 

 cial methods. 



Beside the theories above stated, various remedies and nos- 

 trums have been proposed, some of which afford rational 

 subjects of experiment. One of these recommendations is 

 early planting, which has been considered favorable to the 

 production of a healthy crop. Others recommend ashes, lime, 

 and various alkaline substances, as remedies, having observed 

 some good effects resulting from the use of them. These and 

 several other appliances and methods of cultivation, though 

 they do not insure a sound and healthy crop, may be found to 

 diminish its liability to be diseased. 



We cannot reasonably feel sanguine of discovering a specific 

 for the cure or prevention of the disease, nor of ascertaining 



