Its cause, and a remedy for it. 447 



that buffaloes had drunk up all the upper Missouri, and 

 cut off the supply, we should be at a loss which most to 

 pity, the faith of the narrator, or the probable condition of 

 the buffaloes after their feat of imbibition. 



But the most curious xesnlis folloio these feats of suction. 

 The limbs and trunk beloiv shrink and turn black, for want 

 of that elaborated sap extracted by the aphides. And yet 

 every year we perform artificially this very operation in 

 ringing or decortication of branches, for the purpose of ac- 

 celerating maturation, or improving the fruit. Every year 

 the saro takes off a third, a half, and sometimes more, of a 

 living tree ; and the effect is to produce new shoots, not 

 death. Is an operation which can be safely performed by 

 mcin, deadlt/ when performed by an insect? Dr. Mosher 

 did not detect the insects without extreme search, and then 

 only in colonies, on healthy branches. Do whole trees 

 wither in a day by the mere suction of such insects 1 Had 

 they been supposed to poison the fluids, the theory would 

 be less exceptionable, since poisons in minute quantities 

 may be very malignant. 



While we admit a limited mischief of insects, they can 

 never be the cause of the prevalent blight of the middle 

 and western States, — such a blight as prevailed in and 

 around Cincinnati in the summer of 1844, — nor of that 

 blight which prevailed in 1832. The blight-beetle, after 

 most careful search and dissection, has not been found, nor 

 any trace or passage of it. Dr. Mosher's insect may be 

 set aside without further remark. 



I think that farther observation will confirm the follow- 

 ing conclusions : — 



1. Insects are frequently found feeding in various ways 

 upon blighted trees, or on trees which afterwards become so, 



2. Trees are fatally blighted on which no insects are dis- 

 cerned feeding, — neither aphides nor Scolytus jjyri. 



3. Multitudes of trees have such insects on them as are 

 in other cases supposed to cause the blight, without a sign 

 of blight following. This has been the case in my own 

 garden. 



III. Cause of the blight. — The Indiana Horticultural So- 

 ciety, early in the summer of 1844, appointed a committee 

 to collect and investigate facts on the Fire-Blight. While 

 serving on this committee, and inquiring in all the pear- 

 growing regions, I learned that Reuben Reagan, of Putnam 



