These loathsome animals, however unwelcome, attend in troops, and add to the afflictions of the unfortunate and lazy; but they are routed by the hand of industry and cleanliness.

In examining the louse with a microscope, its external deformity strikes us with disgust. It has six feet, two eyes, and a sort of sting, proboscis, or sucker, with which it pierces the skin, and sucks the blood. The skin of the louse is hard and transparent, with here and there several bristly hairs: at the end of each leg are two claws, by which it is enabled to lay hold of the hairs, on which it climbs. There is scarcely any animal known to multiply so fast as this unwelcome intruder: from an experiment of Lieuenhoek, a louse in eight weeks, may see five thousand of its descendants.

Among the ancients, what is called the lousy disease was not uncommon: Antiochus, Herod, and others are said to have died of this disorder.