RELATION OF DISEASE TO SOILS AND MANURES. 53 



(207.) It is found in wet soils, and also in the dry sandy 

 soils round London ; and, in fact, there is no kind of earth 

 which will protect the plant from the malady. Mr. La- 

 tham, a large potatoe grower at Wressall Castle, York- 

 shire, states, in a letter to me, " that fresh land, poor land, 

 sand land, clay land, and good warp land, are all equally 

 susceptible of its influence, and at about the same time." 



(208.) Mr. Greatrex informs me " that all newly tilled 

 land has answered best, and in some situations near here 

 there may be two bushels of potatoes per rood, good and 

 bad, which is less by more than one-half than the average 

 crop. In land well limed and another well sooted, although 

 seed was used from Bedfordshire, where no disease ap- 

 peared, the crop was equally bad." 



(209.) I have also seen the disease in one case where 

 a potatoe tuber had fallen accidentally under some old 

 planks, and in this situation was completely sheltered from 

 all moisture ; in fact, the bank was so dry, that it was 

 wonderful how any plant could live at all. 



(210.) Perhaps the most curious case is that of an old 

 potatoe throwing out diseased tubers, when it had never 

 been in any soil, or even out of the house. In this in- 

 stance it was no doubt the propagation of the disease from 

 a formerly damaged tuber, a phenomenon which I shall 

 hereafter more fully explain. 



(211.) There is, then, no reason for believing that the 

 disease has been produced by the influence of peculiar and 

 inappropriate soils, but, on the contrary, there is every 

 reason to suppose that it has not had its origin from this 

 cause. Although, however, it has not been produced by 

 soils, it is nevertheless the concomitant testimony of all ob- 



