Of the Oak gall, or Gall-nut;* that it is not a fruit, but an excrefcence 

 produced on the leaves of the oak, by means of an infeSl ; the manner 

 of its formation particularly defcribed. Afmiilar excrefcence produced 

 in like jnanner on the T/iiJile. 



VV HILE I was employed in the fummer feafon, to colleft 

 acorns from the oak, in order to examine the beginning plant in 

 that feed, I faw with furprize, that the gall-nuts were produced 

 upon the leaves of the trees. This feemed the more extraordi- 

 nary, becaufe I had fuppofed that they were the fruit of the tree, 

 but now I found that' they were occafionally, or accidently pro- 

 duced on the leaves of the oak. I was convinced of this, partly, 

 becaufe I faw but a few leaves here and there with gall-nuts on 

 them, (in fome of which I found four, five, and even fix galls) 

 and in others I could not find a fingle one ; and in the next 

 place, becaufe I faw, that thefe galls were formed upon the large 

 fibres, or vellels in the leaves, which were burll or broken, in 

 the places where the galls were formed ; fo that I concluded that 

 fome infe6l had wounded or gnawed thofe vefiTels, and that the 

 juices of the tree, flowing out of the wounded part, had extended 

 themfelves in globules and vefTels, and thus, at length caufed the 

 formation of the gall-nut. 



* This is a literal tranflation of the Dutch word Gahoot, ufed by the Author; in the 

 Latin tranflation it is Galla, which Ainfworth renders ' a fruit called gall, or oak-apple;' 

 but this is a miftake, for the oak-apple is not the gall, nor is it formed on the leaves of the 

 tree, but at the ends of the fmall twigs ; and it is produced, not by a fingle infe(ft, but by 

 a great number colleded together, and thofe of a different fpecies from the infedl found 

 in the gall-nut. 



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