Under the generic name of rat several species of little animals have been comprised and confounded; but we appropriate this name solely to the common rat, which is of a blackish colour, and lives in our houses; they generally inhabit barns and granaries, from whence, when food is scarce they invade our dwellings. The rat is carnivorous, or if the expression may be allowed, an omnivorous animal; he prefers hard substances to soft ones, he gnaws wool, linen, and furniture of all sorts; eats through wood, makes holes and hiding places in walls, ceilings, and behind wainscots, from whence he issues in search of food, and frequently returns with as much as he can drag along, forming, especially when he has young to provide for, a magazine of the whole. The females bring forth several times in the year, though mostly in the summer, and have five or six at a time. They love warmth, and in winter they generally shelter themselves near chimneys, or among hay and straw. In defiance of cats, poison, and traps, these animals multiply so much as frequently to do considerable damage. In old country-houses, where great quantities of grain are kept, and where neighbouring barns and hay-stacks favour their retreat and their increase, they often become so numerous that the inhabitants are under the necessity of quitting their dwellings, unless they happen to devour each other, and this is no uncommon thing when they are straightened for provisions; for in case of a famine being occasioned by their numbers the strong kill the weak, open their heads, first eat the brains, and then the rest of the body: the next day hostilities are renewed in the same manner, nor do they suspend their havock until the majority are destroyed; and this is the reason why, in a place that has been for some time infested with rats, they seem to disappear of a sudden, and return not for a long time. It is the same with field-mice, whose prodigious increase is checked solely by their cruelties to each other when provisions become scarce. Aristotle attributes their sudden destruction to the effect of rains, but rats are not exposed to the weather, and field-mice know well how to secure themselves from its effects, for their subterraneous habitations are not even moist.