Fire Blight of the Pear Tree. 139 



tree put out new bloom and ripened fruit of a small size, but 

 the disease has finally got the better of me by its progress 

 up the trunk above the inarching. 



In two or three instances, where I discovered its existence 

 on the trunk, I carefully cut off the affected bark to the 

 wood, and I am induced to believe saved my trees, for I find 

 the parts healing over. The only remedy, so far as my ob- 

 servations go, is amputation below the affected parts. The 

 first appearance of the disease on the tree is various, I presume 

 owing to the quantity of sap in the vessels, and the activity 

 of its motion. In dwarf or stunted trees, it is frequently 

 observed in blotches on the body, which continue to spread 

 and dry until the whole is encircled ; these blotches fre- 

 quently appear in different parts of the body, and, to out- 

 ward appearance, not at all resembling the disease on the 

 more luxuriant growing trees. Here its attacks are not con- 

 fined to the body, but all parts are subject alike to it, and, 

 instead of drying up, it assumes a corrupt and angry appear- 

 ance, not unfrequently exuding the corrupted sap through 

 the bark, which finally turns black, cracks, and becomes the 

 nursery of minute insects, which are not unfrequently doomed 

 to the slanderous charge of being the authors of the mis- 

 chief I do not perceive that the time of attack is confined 

 especially to any portion of, but extending equally through, 

 the summer. My soil is a dark vegetable mould, on a lime- 

 stone and clay bottom, with an eastern slope, inclining to 

 the north, not subject to excessive moisture or greatly affected 

 by drought. 



Your readers will judge how far the above facts sustain 

 the theory of this blight being the effect of freezing, which 

 supposes it to be confined to a late luxuriant growth, or the 

 supposed effects of a minute poisonous insect or aphis, snugly 

 lodged at the footstalk of the leaf 



The disease, or its cause, has no affinity to what is termed 

 in Professor Harris's Treatise on Insects, the " American 

 blight," but very distinct in every respect. My desire to 

 draw the attention of the scientific inquirer to the subject, I 

 hope will be deemed a sufficient apology for thus particular- 

 izing and saying some things which have been said before. 



Spring Garden, Cincinnati, Feb. 16^/j, 1846. 



