On the Lycoperdon cancellatum. 179 



August and September. These minute globular bodies I 

 concluded to be the seeds of a species of fungus ; but as a 

 few only of the leaves of my trees were affected, and no 

 very injurious effects were visible, I did not take any mea- 

 sures to prevent their dispersion over my garden. 



I did not, however, long remain ignorant of the formida- 

 ble nature of my new enemy ; for within two years, every 

 Pear tree in my garden became in some degree diseased. 

 The leaves only, at first, appeared to be injured ; but the 

 disease soon extended itself to the annual branches, in many 

 protuberant yellow spots, beneath which the bark was found 

 to have acquired a bright yellow colour : and as far as this 

 colour extended, the bark, and the wood beneath it, invaria- 

 bly perished, either in the same or following season, leaving 

 wounds similar to those inflicted by canker, but less curable. 

 The fruit also became diseased and worthless, and almost 

 all the young shoots, when once attacked, perished in the 

 following winter. These effects were not confined to my 

 garden, but extended to the Pear trees in an orchard which 

 was two hundred yards distant ; and I cannot entertain a 

 doubt, but that the disease was communicated to these by 

 seeds which had been conveyed by the prevalent west 

 winds. I endeavoured, during the summers of 1813 and 

 1814, to check its progress in my garden, by picking off 

 every diseased leaf; but I found all my efforts nearly abor- 

 tive, and I have been obliged to destroy the greater part of 

 my Pear trees : those which remain, have become annually 

 more diseased, and I fear never can be ultimately preserved, 

 unless a remedy for the disease can be discovered. 



I tried the effect, in the last season, of sprinkling the 



