One of the most curious chapters in the life of this hardy beast is now developing in the far island of South Georgia, on the border of the Antarctic, east of Cape Horn. On this island, which has a cold and stormy summer and nine months of rigorous winter, several whaling stations have been established. For years great numbers of whale carcasses have drifted ashore each season and, half rotting, half refrigerated, have furnished a never-failing food supply for brown rats that have landed from the ships. With such abundant food they are reported to have increased until they now exist there literally in millions. They make their nests in the tussocks of grass and peat and swarm along well-marked trails they have made on the mountain sides. In the trenches along the battle front in France they have become extremely abundant and troublesome, and in England have multiplied until the Board of Agriculture is recommending efforts to destroy them as a menace to the public welfare through their waste of food supplies. On farms, in addition to destroying growing and stored crops, they kill great numbers of young chickens, turkeys, and other poultry, and create havoc with such ground-frequenting game as pheasants. At all times brown rats are more or less carnivorous, and when several are confined in a cage the stronger will soon kill and devour the weaker. In city department stores and large hotels they often cause thousands of dollars damage yearly in single establishments. An English organization for their destruction estimated in 1908 that, outside the towns and shipping, in Great Britain and Ireland they caused annual losses of about $73,000,000. When there is a sudden diminution in the food supply, an abundance of which has caused a great increase in the rat population, the rats migrate into other districts, sometimes in enormous numbers. These migrations usually occur at night, and many are matters of history in Europe and in the United States. A witness of one of these migrations in Illinois in 1903 reported that one moonlight night as he was passing along the roads he heard a rustling in a field near by and soon saw crossing the road in front of him a multitude of rats extending as far as he could see. The following year the invaders became a plague in that district. At times of food scarcity rats become extremely bold and aggressive. Without hesitation they swim streams encountered in their wanderings and at times will even attack man. Owing to their great numbers, universal distribution, and destructiveness, brown rats are the worst mammal pest known to mankind. Through their habit of living in sewers, among the offal of slaughter-houses, and in garbage heaps, from which they invade dwellings and storehouses, they pollute and spoil even more foodstuffs than they eat.