Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 2 - By Alexander Von Humboldt And Aime Bonpland.
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We Often Repeated This Experiment On Ourselves In The
Valley Of The Rio Magdalena.
It may be asked whether the insect
deposits the stimulating liquid only at the moment of its flight, when
it is driven away, or whether it draws the liquid up again when left
to suck undisturbed.
I incline to this latter opinion; for on quietly
presenting the back of my hand to the Culex cyanopterus, I observed
that the pain, though violent in the beginning, diminishes in
proportion as the insect continues to suck, and ceases altogether when
it voluntarily flies away. I also wounded my skin with a pin, and
rubbed the pricks with bruised mosquitos, and no swelling ensued. The
irritating liquid, in which chemists have not yet recognized any acid
properties, is contained, as in the ant and other hymenopterous
insects, in particular glands; and is probably too much diluted, and
consequently too much weakened, if the skin be rubbed with the whole
of the bruised insect.
I have thrown together at the close of this chapter all we learned
during the course of our travels on phenomena which naturalists have
hitherto singularly neglected, though they exercise a great influence
on the welfare of the inhabitants, the salubrity of the climate, and
the establishment of new colonies on the rivers of equinoctial
America. I might justly have incurred the charge of having treated
this subject too much in detail, were it not connected with general
physiological views. Our imagination is struck only by what is great;
but the lover of natural philosophy should reflect equally on little
things.
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