The rapid spread of the rat is due to the fearlessness with which he will follow man and his commissariat wherever he goes. Scarcely a ship leaves a port for a distant voyage but it takes in its complement of rats as regularly as the passengers, and in this manner the destructive little animal has not only distributed himself over the entire globe, but, like an enterprising traveller, continually passes from one country to another. The colony of four-footed depredators, which ships itself free of expense, makes, for instance, a voyage to Calcutta, whence many of the body will again go to sea, and land perhaps at some uninhabited island where the vessel may have touched for water. In this manner many a hoary old wanderer has circumnavigated the globe oftener than Captain Cook, and set his paws on twenty different shores. The rat-catcher to the East-India Company has often destroyed as many as five hundred in a ship newly arrived from Calcutta. The genuine ship-rat is a more delicate animal than the brown rat, and has so strong a resemblance to the old Norman breed, that we cannot help thinking they are intimately related. The same fine large ear, sharp nose, long tail, dark fur, and small size, characterize both, and a like antipathy exists between them and the Norwegian species. It is by no means uncommon to find distinct colonies of the two kinds in the same ship--the one confining itself to the stem, the other to the stern of the vessel. The same arrangement is often adopted in the warehouses of seaports, the ship's company generally locating themselves as near the water as possible, and the landsmen in the more inland portion of the building.