INDIANA HORTICULTURAL SOCIETY. 417 



3. Multitudes of trees have such insects on tliem as are supposed to 

 cause the blight in other cases, without a sign of blight following. This 

 has been the case in my own garden. 



III. Cause of the Blight— The Indiana Horticultural Society, early in 

 the summer of 1844, appointed a committee to collect and investigate facts 

 on the fire-blight. While serving on this committee, and inqviiring in all 

 the pear growing regions, I learned that Reubeu Ragan, of Putnam 

 County, Indiana, was in possession of much information and supposed 

 himself to have discovered the cause of this evil, and to him I am indebted 

 for the first suggestion of the cause. Mr. Ragan has for more than twelve 

 years past suspected that this disease originated in the fall previous to 

 the summer in which it dec^res itself. During the last winter Mr. Ragan 

 predicted the blight, as will be remembered by some of his acquaintances 

 in Wayne County, and in his pear orchards he marked the trees that 

 would suffer, and pointed to the spot which woiild be the seat of the 

 disease, and his prognostications were strictly verified. After gathering 

 from him all the information which a limited time would allow, I 

 obtained from Aaron Aldridge, of this place (Indianapolis), a nurseryman 

 of great skill, and possessed of careful, cautious habits of observation, 

 much corroborative information, and particularly a tabular account of the 

 blight for nine years past in his nursery and orchard. 



The spring of 1843 opened early, but cold and wet until the last of 

 May. The summer was both dry and cool, and the trees made very little 

 growth of new wood. Toward autumn, however, the drouth ceased, 

 copious rains saturated the gi'ound, and warm weather started all trees 

 into late but vigorous growth. At this time, while we hoped for a long 

 fall and late winter, on the conti-ary, we were surprised by an early and 

 sudden winter, and with unusual severity at the very beginning. In this 

 region much corn was ruined and more damaged; and hundreds of bushels 

 of apples were caught on the trees and spoiled, one cultivator alone losing 

 5(X) bushels. Caught in this early winter, what was the condition of fruit 

 trees? They were making rapid growth, every part in a state of excite- 

 ment, the wood unripe, the passages of ascent and descent impeded with 

 sap. In this condition the fluids were suddenly frozen, the gi-owth in- 

 stantly checked and the whole tree, was, from a state of great excitability, 

 by one shock, rudely forced into a state of rest. Warm suns for a time 

 followed severe nights. What would be the effect of this freezing and 

 sudden thawing upon the fluids and their vessels? I have been able to 

 find so little written upon morbid vegetable anatomy (probably from the 

 want of access to books) that I can give but an imperfect account of the 

 derangement produced by the circulating fluids by congelation. We can 

 not state the specific changes produced by cold upon the ascending sap, or 

 on the cambium, nor upon the elaborating descending current. There is 

 i-eason to suppose that the two latter only suffer, and probably only the 

 last. That freezing and thawing decomposes the coloring matter of plants 



27— Board of A. 



