APPENDIX. 181 



it must, however, be conceded, that seed potatoes kept until July for 

 the purpose of late planting, may have become deteriorated, because those 

 roots being biennial cannot be expected to retain their health and vigour 

 to so late a period ; which, in some measure, accounts for early varieties 

 being more seriously affected by the extreme heat than the lale keeping 

 red-skinned varieties, which will retain their vegetative properties even 

 in dry seasons, so as to produce a good crop if not retarded by being 

 over heated, to which they are liable, especially if placed in contact 

 with acrid manure, which is destructive to all descriptions of plants in 

 hot dry weather. New land without manure generally produces the 

 best crops in dry seasons 



It may be observed farther, that when the leaves or vines of the 

 potato wither prematurely through extreme heat, the tubers become af- 

 fected to such a degree, that rain late in the season hastens their de- 

 struction instead of nurturing them, they consequently return to their 

 native element. 



From the above considerations, as well as from the knowledge I have 

 acquired of the nature of plants in general, I have come to the conclu- 

 sion that the alleged disease in potatoes was not occasioned by defective 

 seed, but by the extreme heat of the Summer, followed by the excessive 

 rain in Autumn.* In some instances the defect may have been acceler- 

 ated by an injudicious use of acrid manure, and in others from their 

 being planted in low undrained ground. It often happens that potatoes 

 deteriorate from not being properly dried when taken from the ground, 

 which on being heaped together, become heated, and consequently rot 



All which is respectfully submitted. 



THOMAS BRIDGEMAN. 

 NEW- YORK, February 1st, 1845 



* As this review was elicited by the discussions relative to the defect in potatoes the last 

 two years, the conclusion has special reference thereto. It must, however, be acknowledged, 

 that the extremes of HEAT, COLD, and MOISTURE, are alike detrimental to vegetation in all 

 seasons ; and that hot dry summers are often attended with icsuJtt as fatal to vcfetabk 

 productions as the coldness of winter. 



