CULTIVATION OF POTATOES. 285 



of the malady have been, from the beginning, that the cause is atmospheric, and that certain 

 states of the weather have been, and are the proximate cause of the potato disease. If so, it may 

 be asked, why are not all fields equally affected ? inasmuch as all are equally exposed to the 

 action of the weather. So too, I might inquire, why does not the cholera affect the people of 

 a country alike ] At some points it seems to be intensely active, while at others it is scarcely 

 felt, and others escape entirely. That it is connected, as a sequence, with certain states of the 

 weather, appears to be sustained by the fact that the disease is quite uniformly a sequence of 

 that state ; it appears to follow certain changes. One of the signs of an attack of the malady 

 is the desiccation of the leaf and stem ; and again, it attacks the unripencd crop. So again, 

 other vegetables are affected in their foliage in the same way : of these vegetables the American 

 elm is very generally attacked ; its leaves begin to wither and dry upon their edges, and some- 

 times all the leaves upon a young and succulent branch dry and crisp, when the limb dies. I 

 have seen the plum, maple and horse-chestnut affected simultaneously with the elm and potato 

 plant, and to manifest those symptoms immediately after a certain condition in the state of the 

 weather had passed. This state is marked by a peculiar sultriness, and sharpness of heat, which 

 Las followed almost immediately upon a rain which had supplied vegetation with an abundance 

 of water. The rot is a sequence of this state ; it certainly is not an antecedent. This view of 

 the matter explains to us how all the investigations have failed : that they should fail is plain 

 to every reflecting mind. The time may possibly come when the peculiar cause of cholera 

 may be detected by experiment. Physicians have sought for the cause by dissecting the dead ; 

 but it is evident that it can not be found here, any more than chemists have been able to find 

 the cause of the potato rot by dissecting and analyzing the tuber. What, however, is discovered 

 are effects of disease, in both cases ; not, however, a trace of a cause can be seen. The disease 

 is really a gangrene of the cellular part ; it is in the walls of the celluar system : the starchy 

 part is unaffected. This fact I determined the first season that it appeared in this State, and 

 the foregoing views were adopted at this early period, and have been stated repeatedly in the 

 various discussions in which I have taken a part. My observations have been directed to facts, 

 as they have transpired every season since the appearance of the gangrene, and I have had an 

 increasing conviction of their truth, or rather increasing cAidence of their correctness every 

 year. It is important that we find something upon which to form an opinion ; we know better 

 what to do, and what to withiiold. We shall not attempt to destroy insects, expecting thereby 

 to rid us of the malady. 



Observation is valuable, as it will enable us to diminish the amount of disease, though we 

 may be unable to escape it entirely. This is apparent from, 1. The fact that certain varieties, 

 the dark colored for instance, are less subject to gangrene than the white. 2. By the early 

 planting of any kind, it stands a better chance to escape it, than by late planting. 3. Clay 

 soils, which are moist or wet, favor the gangrene, and sandy and gravelly soils are safer of the 

 two. 4. Nitrogenous manures, applied in the hills, favor the development of the gangrene. 

 5. The use of wood ashes as a fertilizer. These five facts are important, though the observa- 

 tion of the rules which flow from them may not save us entirely from the disease ; the gene- 



