APHIS. 
175 
“ In the height of Summer, when the weather 
is hot and dry, and Aphides are most abundant, 
the foliage of trees and plants, (more especially in 
some years than others) is found covered with and 
rendered glossy by a sweet clammy substance 
known to persons resident in the country by the 
name of honey-dexo : they regard it as a sweet sub- 
stance falling from the atmosphere, as its name 
implies. • The sweetness of this excrementitious 
substance, the glossy appearance it gave to the 
leaves it fell upon, and the swarms of insects this 
matter attracted, first led me to imagine that the 
honey-dew of plants was no other than this secre- 
tion, which farther observation has since fully con- 
firmed. Others have considered it as an exsuda- 
tion from the plant itself. Of the former opinion 
we find the Rev**. Mr. White, one of the latest 
writers on natural history that has noticed this sub- 
ject. But that it neither falls from the atmosphere, 
nor issues from the plant itself is easily demon- 
strated. If it fell from the atmosphere, it would 
cover every thing indiscriminately, whereas we 
never find it but on certain living plants and trees. 
We find it also on plants in stoves and green- 
houses covered with glass. If it exsuded from the 
plant, it would appear on all the leaves generally 
and uniformly ; whereas its appearance is ex- 
tremelj^ irregular, not alike on any two leaves of 
the same tree or plant, some having none of it, 
and others being covered with it but partially. 
But the phenomena of the honey-dew, with all 
their variations, are easily accounted for by con- 
