ABOUT FRUITS, FLOWERS AXD FARMIXG. 399 



insect — " very minute hrowjv-colored aphides^ snugly secreted 

 iu the axilla of every leaf on several small branches; . . . 

 most of them were busily engaged with their proboscis 

 inserted through the tender cuticle of this j^art oi t\\Q 2^etiole 

 of the leaf, feasting upon the vital juices of the tree. The 

 leaves being thus deprived of the necessary sap for nourish- 

 ment and elaboration soon perished, . . , while all that part 

 of the branch and trunk below, dependent upon the elabo- 

 rated sap of the deadened leaves above, shrunk, turned 

 black, and dried up," p. 261, 



Lindley, in his work on Horticulture^ p. 42-4G, has de- 

 tailed experiments illustrating \egeXah\e petspiration, from 

 which we may form an idea of the amount of fluid which 

 these " very minute brown-colored aphides " would have to 

 drink. A sunflower, three and a half feet high, perspired 

 in a very warm day thirty ounces — nearly two pounds ; on 

 another day, twenty ounces. Taking the old rule, " a pint 

 a pound," nearly a quart of fluid was exhaled by a sun- 

 flower in twelve hours ; and the vessels were still inflated 

 Avith a fresh supply drawn from the roots. Admitting that 

 the leaves of a fruit-tree have a less current of sap than a 

 sunflower or a grape-vine, yet in the months of May and 

 June, the amount of sap to be exhausted by these very 

 minute brown aphides, would be so great, that if they 

 drank it so suddenly as to cause a tree to die in a day, they 

 would surely augment in bulk enough to be discovered 

 without a lens. If some one had accounted for the low 

 water in the Mississippi, in the summer of 1843, by saying 

 that buflaloes had drank 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 

 buffidoes after their feat of imbibition. 



But the most curious results /o/^omj these feats of suction. 

 The limbs and trunk bdow 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 



