In travelling upon small dirty steamers in the Orient I have often slept on deck, quite as much to avoid the rats and vermin in the state-rooms as for better ventilation. In a certain ship in which I travelled some of the ship's officers amused themselves by shooting rats with an air-rifle in the lower decks, quietly hiding themselves in dimly-lighted places and shooting the rats as they crossed the lighter spaces. In many ships the rat population far exceeds the human population. In San Francisco 310 rats were destroyed by a single fumigation on a vessel of only 260 tons burden. In Bombay 1300 rats were destroyed at one time upon a single ship and in London 1700 were secured at one fumigation. The ease with which rats adapt themselves to new environment is shown by the fact that they live, when permitted to do so, in cold storage and refrigerating rooms where they grow heavy coats of fur for protection against the cold. They gain ingress to ships in three principal ways: (1) By coming overside upon gang-planks, wharf stringers, etc. (2) By passing along the lines by which the ship is made fast to the dock, through hawse holes, the rat being an expert rope walker. (3) By coming aboard in the cargo. By the latter method rats are often brought aboard by whole families, their fleas included. Many styles of packages such as barrels, bales, crated goods, grain in sacks and matting in rolls present the rat with abundant opportunity to take passage and it is probably thus, as stowaways, that rats go to sea in the largest number. Plainly, then, the placing of rat-funnels upon all lines from ship to wharf, the use of special fenders, the raising of gang-planks and even anchorage in the stream will not prevent rats from getting aboard ships unless cargo disinfection be practised before loading the vessel. The ship itself should be fumigated every three months if possible. Rats are doubtless carried in considerable numbers upon railway cars, both freight and passenger. While riding in a street car in Manila in 1908 I saw a rat run along the window ledge, to the mingled fright and amusement of the passengers. The same principles which apply in the case of ships apply to cars and trains as well. Grain cars in particular should receive especial attention.