1846.] The Potato Disease. 311 



the leaf during a continuance of, or immediately after dark an I 

 wet weather. Before this took place last year many of the tubers 

 had arrived at a tolerably ripe state and withstood the disease, 

 while the rest, being without their due supply of carbon or fibrous 

 tissue, had not strength to resist it. But those which last year 

 withstood the disease, and those even in many districts in which 

 it did not manifest itself at all, had, from want of sunlight, re- 

 ceived too small a supply of carbon into their system, and the 

 seed of this season everywhere was consequently predisposed to 

 disease. The result has been that under similar favorable circum- 

 stances of dark and moist atmosphere the entire crop oi'the coun- 

 try has now become diseased. Last year the disease was four 

 weeks later in manifesting itself, but last year was a later season 

 by four weeks than this; besides that, the seed used this year 

 was, for the causes already stated, more readily affected. The 

 fact that the disease last year did not manifest itself on some parts 

 of a farm, while other parts of the same farm, equally exposed to 

 sunlight, did not escape, may ajise from this: that those parts 

 which did escape (generally mossy), from their sponges and per- 

 haps antiseptic nature, gave a drier and safer bed to the tuber, 

 which consequently remained sound, and the stem and leaves con- 

 tinuing green, a longer time was given for the elaboration of car- 

 bon on the subsequent appearance of sunlight. 



But even in the most favorable positions this process appears 

 to have been imperfectly performed ; for this year neither moss- 

 lands nor the seed from moss-lands have escaped. When a par- 

 tial failure takes place in any of the grain crops, the extent of it 

 is not observed till the crop is being thrashed out; but in the case 

 of potatoes the universal decay of the haul n causes forebodings 

 perhaps needlessly great. Last year nearly half the crop was 

 saved, and this year, bad though appearances are, it is hoped the 

 loss will not be total. Next year the potato will be still more 

 predisposed to disease, and the failure will be still greater should 

 the season prove unfavorable. But should the season, on the con- 

 trary, be in the latter part of it clear, sunny, and dry, we may 

 hope that the tubers will receive such an accession of strength as 

 may restore them to their former hardiness. This country has 

 often sustained severer losses by the partial destruction of the 

 grain crops from unfavorable seasons than it has ever yet suffered 

 from the ravages of the potato disease. A succession of bad grain 

 crops has more than once been experienced, caused by dark and 

 moist weather more readily affecting the produce of seed, which 

 itself was never properly matured. And this predisposition to 

 disease continued till a succession of sunny seasons for a time 

 altogether dispelled it. The early part of this season was clear 

 and sunny, and the crop of early potatoes, then ripening, received 



