The Potatoe Plague. 51 



neither do I see any reason even to guess such a cause of the 

 potatoe plague. 



A great number of experimentalists contend that the pota- 

 toe rot is attributable to the fermentation of animal manure, 

 and it strikes me, forcibly, that the rapid, malignant rot of a 

 great proportion of the lost crops, may justly be attributed 

 to this cause. More instances where the result of this mode 

 of treatment has proved fatal to the plant are adduced than 

 of any other. I cannot altogether withhold credence from 

 such a mass of concurrent testimony. Wherever potatoes 

 have been manured with animal matter, and especially barn- 

 yard manure, in the hill, and when they have been planted 

 before such compost has been allowed to disintegrate and as- 

 similate with the soil, the rot seems to have been the invaria- 

 ble consequence. On the other hand, it appears that the 

 disease seldom appears on virgin soil, or newly broken sward 

 land. I the more incline to the belief that this theory is more 

 extensively corroborated in practice than any -of those I have 

 thus far noticed, from the fact that, of the potatoes treated 

 with animal manure, those which lie nigh the outside of the 

 hill are found best and soundest, while those in the centre, 

 among the mahure, are most specked and rotten. 



It is not conclusive, however, that the disease can be stop- 

 ped by planting on new or sward land, inasmuch as potatoes 

 dug from such land sound, have often been found to rot after 

 storing, so as to have been entirely lost before spring. Neith- 

 er does this solution of the mystery suffice, even partially, to 

 account for the extent of the injury in other countries ; for 

 we do not know how potatoes are manured there, or whether 

 they are manured at all. All that can be predicated on the 

 evidence before us is, that manuring with new animal matter 

 is calculated to cause loss and injury. 



There is yet another theory that I feel bound to notice in 

 this connection, inasmuch as it is advanced by a very intelli- 

 gent gentleman, (Mr. Teschemacher, of Boston,) as the result 



