1846.] The Potato Disease. 312 



a due supply of carbon and were perfectly sound. But the dark 

 moist weather which preceded the general appearance of the 

 disease on the later crops, occurred at the time when sunlight 

 was of the greatest consequence. Yet, notwithstanding the pre- 

 sent unfavorable appearance of the crop, it does not follow that 

 the potato is to disappear from the vegetable world, but on the 

 contrary we are entitled to hope that a succession of good years 

 will yet restore it to sound and healthy vitality. 



Lime has been recommended as an antidote to the disease, but 

 the following facts disprove its efficacy: — One field of potatoes 

 on this farm was heavily limed immediately before the potatoes 

 were planted; .about an acre of it was limed after the shaws were 

 a foot high. The disease appeared at the same time over the 

 whole field. On another field lime had been applied last year, 

 on alternate ridges, one ridge receiving about three times the or- 

 dinary dressing (at the rate of 300 bushels per acre), and the next 

 ridge receiving none. The ridges were 30 feet wide, and 12 

 Potato drills were planted this spring on each. The disease ma- 

 nifested itself a week earlier on the limed than on the unlimed 

 ridge, and the greater decay of the shaw on the limed ridge con- 

 tinues still quite evident to the eye. In all these instances the 

 newly cut set had been dusted with quicklime when in prepara- 

 tion for planting. Another part of the field was planted with 

 seed, dipped, when fresh cut, in a weak solution of sulphuric acid 

 ( 1 part acid to 80 of water), according to the recommendation of 

 Professor Johnston, but without averting the disease. 



The practical conclusions I would venture to draw are these — 



1st. That after the stem had blackened and decayed, the tubers 

 do not grow larger, and should as soon as possible be raised and 

 stored; lor though the healthiest tubers might keep equally well 

 in the soil, those which are predisposed to disease are more liable 

 to be attacked when left in it. 



2d. That cutting off the haulm does not appear in any degree 

 to prevent the disease, whilst, so long as it remains green, the 

 haulm is of essential consequence to the healthy functions of the 

 plant. [Our correspondent does not appear to have tried pulling 

 up.] 



3d. That the soundest seed will be likely to be obtained by 

 leaving the tubers in the ground during winter, inasmuch as 

 thereby all the weakest will ceitainly be destroyed and only the 

 strongest and healthiest left; and it may therefore be advisable to 

 leave a portion undug, and to suffer the total loss of the partially 

 diseased for the sake of securing the soundest tubers for seed. 



4th. That the application of lime to the soil or seed seems to 

 have no influence in averting the disease. 



When the potato is taken up it is of the utmost consequence 



