Mosquitoes, and their Uses.—The mosquito is accounted one of the most noxious and the most numerous of insects; at least of such as are esteemed noxious by the vulgar and the ignorant. In some countries, indeed, their numbers, and the effects produced by them, are wonderful. There is no instance on record more striking than the following, as related by Dr. Clarke:—
“No contrivance on our part could prevent millions of mosquitoes from filling the inside of our carriage, which, in spite of gloves, clothes, and handkerchiefs, rendered our bodies one entire wound. The Cossacks light numerous fires, to drive them from the cattle during the night; but so insatiate is their thirst of blood, that hundreds will attack a person attempting to shelter himself even in the midst of smoke. At the same time, the noise they make in flying cannot be conceived by persons who have only been accustomed to the humming of such insects in our country.”—“Almost exhausted by fatigue, pain, and heat, I sought shelter in the carriage, sitting in water and mud. It was the most sultry night I ever experienced; not a breath of air was stirring; nor could I venture to open the windows, though almost suffocated, through fear of the mosquitoes. Swarms, nevertheless, found their way to my hiding-place; and when I opened my mouth, it was filled with them. My head was bound in handkerchiefs; yet they forced their way into my ears and nostrils. In the midst of this torment, I succeeded in lighting a lamp over the sword-case; which was instantly extinguished by such a prodigious number of these insects, that their dead bodies actually remained heaped in a large cone over the burner for several days afterward: and I know not any mode of description which can convey a more adequate idea of their afflicting visitation, than by simply relating this fact: to the truth of which, those who travelled with me, and who are now living, bear indisputable testimony.”
Those who have laboured under so painful a visitation, as that to which this lively account refers, may not perhaps be so ready to admit the general utility of these irritating insects, though their usefulness is more evident, and far more easily proved, than that of the locust, or indeed of most other animals of a similar nature. Bred in the midst of stagnant pools, of bogs, and marshes, in regions unwholesome to man, and where the effluvia arising from animal bodies, and from rank decaying vegetable substances, are so abundant, as to form thick pestilential vapours, that would inflict almost instant destruction on the human inhabitant, and most other creatures, if not removed as quickly as they were formed;—bred in such regions, and gifted with functions and propensities directed to the proper ends, the mosquito supports its existence by consuming the noxious particles exhaled from the swamps; and the bodies of animals, as rapidly as they are generated;—thereby preventing that horrible putrefaction of the air, and consequent pestilence, which would infallibly take place, if the mosquitoes, and similar insects, were not employed to purify the atmosphere.
CHAP. XXXII.
CURIOSITIES RESPECTING INSECTS.—(Concluded.)
Animalcules—The Cheese Mite—The Hydra, or Polypes.
| The smallest creature in existence Has limbs and sinews, blood, and heart, and brain, Life and her proper functions to sustain, Through the whole fabric, smaller than a grain! What more can our penurious reason grant To the large whale, or castled elephant;— To those enormous terrors of the Nile, The crested snake, and long-tail’d crocodile;— Than that all differ but in shape and name, Each destin’d to a less or larger frame? Prior’s Solomon. |
Animalcules.
The microscope discovers legions of animalcules in most liquors, as water, vinegar, beer, dew, &c. They are also found in rain, and several chalybeate waters, and in infusions of both animal and vegetable substances, as the seminal fluids of animals, pepper, oats, wheat, and other grain, tea, &c. &c. The contemplation of animalcules has rendered the term, infinitely small bodies, extremely familiar to us. A mite was anciently thought the limits of littleness; but we are not now surprised, to be told of animals twenty-seven millions of times smaller than a mite. Minute animals are found proportionably much stronger, more active and vivacious, than large ones. The spring of a flea in its leap, how vastly does it outskip any thing the larger animals are capable of! A mite, how vastly swifter does it run than a race-horse! M. De. L’Isle has given the computation of the velocity of a little creature, scarcely visible by its smallness; which he found to run three inches in half a second: supposing now its feet to be the fifteenth part of a line, it must make five hundred steps in the space of three inches; that is, it must shift its legs five hundred times in a second, or in the ordinary pulsation of an artery. The excessive minuteness of microscopical animalcules conceals them from the human eye. One of the wonders of modern philosophy is, to have invented means for bringing objects, to us so imperceptible, under our cognizance and inspection: creatures, a thousand times too little to be able to affect our sense, should seem to have been very safe; yet we have extended our views over animals, to whom these would be mountains. In reality, most of our microscopical animalcules are of so small a magnitude, that through a lens, whose focal distance is the tenth-part of an inch, they only appear as so many points; that is, their parts cannot be distinguished, so that they appear from the vertex of that lens under an angle not exceeding a minute.