Gnats. The common gnat (culex pipieusj is a near relation to the musquito, but is not usually so troublesome to the human species. They both belong to the section Nemocera of the Dipterous insects, whose mouths are furnished with bristly stings, included in flexile sheaths. They pierce the skin by means of the proboscis, in order to feed upon the blood, and, at the same time, inject a poisonous fluid, producing considerable inflammation and swelling, of varying intensity in different persons. Their activity usually commences towards evening, or after sunset. The Laplanders appear to be the greatest sufferers from their attacks; but all latitudes are, more or less, troubled with the species. The Laplanders use tar-cream to prevent the insects biting them, but that could scarcely be used in this country. The common Goulard water, scented with Eau de Cologne, is the best application we know, and is useful in allaying the irritation, as also preventing the attacks. We have observed that gnats seldom or never frequent rooms or houses where chloride of lime has been exposed. We recommend those who are much troubled by gnats to try this remedy.