FIG. 68.-Bedbug (Cimex lectularius): a, Larval skin shed at first molt; b, second larval stage taken immediately after emerging from a; c, same after first meal, distended with blood. Greatly enlarged."

Badly infested rooms may be freed from bedbugs by fumigating with sulphur, using 2 pounds of sulphur to every thousand feet. The method of disinfecting with sulphur is described on page 65.

Roaches.

Roaches are believed to be responsible for the conveyance of tuberculosis, diphtheria, typhoid fever, tonsillitis, and possibly some other diseases. They spread these diseases by carrying the organisms on their feet and in their intestinal canals and disseminating them over food supplies, books, and other articles in daily use. They are especially abundant in the galleys of vessels and in damp kitchens. They appear at night after the lights have been turned off and overrun everything in the room. Roaches can be quickly, cheaply, and completely exterminated from ships and houses by the use of sodium fluorid. This should be spread with a rubber powder blower on the floors near the walls and on shelves in closets. The powder does not suffocate the insects, but sticks to their feet. They clean it off with their mouths, some of it being swallowed and causing the death of the insect. As sodium fluorid is poisonous to man in doses of a tablespoonful or more care should be taken not to spread it over articles that are to be eaten.

SANITATION OF VESSELS.

Construction.-Section 2 of an act of Congress entitled "An act to promote the welfare of American seamen in the merchant marine of the United States," etc., approved March 4, 1915, reads as follows:

SEC. 2. That on all merchant vessels of the United States the construction of which shall be begun after the passage of this act, except yachts, pilot boats, or vessels of less than one hundred tons register, every place appropriated to the crew of the vessel shall have a space of not less than one hundred and twenty cubic feet and not less than sixteen square feet, measured on the floor or deck of that place, for each seaman or apprentice lodged therein, and each seaman shall have a separate berth and not more than one berth shall be placed one above another; such place or lodging shall be securely constructed, properly lighted, drained, heated, and ventilated, properly protected from weather and sea, and, as far as practicable, properly shut off and protected from the effluvium of cargo or bilge water. And every such crew space shall be kept free from goods or stores not being the personal property of the crew occupying said place in use during the voyage.

That in addition to the space allotment for lodgings hereinbefore provided, on all merchant vessels of the United States which in the ordinary course of their trade make voyages of more than three days' duration between ports, and which carry a crew of twelve or more seamen, there shall be constructed a compartment, suitably separated from other spaces, for hospital purposes, and such compartment shall have at least one bunk for every twelve seamen constituting her crew, provided that not more than six bunks shall be required in any case.

Every steamboat of the United States plying upon the Mississippi River or its tributaries shall furnish an appropriate place for the crew, which shall conform to the requirements of this section, so far as they are applicable thereto, by providing sleeping room in the engine room of such steamboat, properly protccted from the cold, wind, and rain by means of suitable awnings or screens on either side of the guards or sides and forward, reaching from the boiler deck to the lower or main deck, under the direction and approval of the Supervising Inspector General of Steam Vessels, and shall be properly heated.

All merchant vessels of the United States, the construction of which shall be begun after the passage of this act, having more than ten men on deck must have at least one light, clean, and properly ventilated washing place. There shall be provided at least one washing outfit for every two men of the watch. The washing place shall be properly heated. A separate washing place shall be provided for the fireroom and engine-room men, if their number exceed ten, which shall be large enough to accommodate at least one-sixth of them at the same time, and have hot and cold water supply and a sufficient number of wash basins, sinks, and shower baths.

The sides of an iron ship are cold and anyone sitting or sleeping near them becomes chilled. In order to prevent this, spaces used for quarters should have the outside walls sheathed with plating, an air-tight space being left between the side plates of the ship and this plating. If the space is not air-tight the circulation of air within will cause sweating. The inside of this space should be lined with cork or asbestos or painted with cork paint.

Ventilation. The ventilation of sailing ships is simple. All they require are a few air ducts leading from the deck to the forecastle cabin and galley. These ducts end in cowls, which can be turned to the wind to admit air into the compartments or away from the wind to draw it out. On steam vessels provision has to be made for removing the large amount of air heated by radiation from the surface of boilers and steam and hot-water pipes. This heat is called "wild heat," as it serves no useful purpose. There must be a number of large size ventilating pipes and fans or other apparatus employed throughout the ship to draw cold air in and force hot air out. The drawing in of the air is the more important, as a large part of the hot air is used in the combustion of fuel and escapes through the smokestack. The fireroom is said to be more comfortable in assisted draft. In this condition the natural intakes are closed and the air is drawn through the ventilators into the fireroom by fans. The hot air leaves by the same openings as in natural draft. Gatewood says:

In order to diminish the temperature in firerooms and thus improve the conditions under which the men work, the use of assisted draft is becoming much more common, and by reducing number of fires it seems not improbable that the expenditure of coal may thus be made as economical under assisted draft as under natural draft at ordinary cruising speed.

On passenger and war vessels there must be a system of ventilating pipes extending to all parts of the vessel, connected to fans operated by electric motors; the fresh air should be driven into the living

quarters and the stagnant air drawn out of places such as the galley, bathrooms, and water-closets. If some such system of ventilation were not provided, conditions aboard these vessels would be unbearable.

The temperature in the fireroom often rises as high as 130° F. The temperature and humidity of the fireroom should, if possible, be regulated so as to prevent the wet-bulb thermometer from rising above 81° F. Firemen, while on duty should be allowed plenty of ice water. If no ice water is obtainable, oatmeal water should be provided. A water butt should be placed where the men can easily get to it. When coming out of the fireroom into the cold outer air the men should protect themselves with adequate clothing and not rush out in undershirt and overalls. Owing to their carelessness in this respect, men of this class are subject to frequent colds, rheumatism, and kidney disease. They should spend at least 2 hours of the 24 on deck. The hours spent in the hot furnace room makes them "tender" to even a moderately cold atmosphere and it is difficult to induce them to spend a sufficient time in the open air. This applies also to cooks, stewards, and all persons whose work is inside the ship. Water. The safest water to use on board a vessel is that provided by distillation. When it is not possible to have distilled water, great care should be exercised to procure water that has not been contaminated by sewage. An act of Congress approved June 4, 1914, states that

No person, firm, or corporation shall furnish water for drinking or cooking purposes to any vessel in any harbor of the United States intending to clear for some port within some other State or Territory of the United States, or the District of Columbia, taken from the waters of such harbor or from any other place where it has been or may have been contaminated by sewer discharges: Provided, That water in regard to the safety of which a reasonable doubt exists may be used if the same has been treated in such a manner as to render it incapable of conveying disease, and the fact of such treatment is certified by the interstate sanitary officer, or the State or other health authority within whose jurisdiction it is obained.

In foreign ports water of known purity should be obtained if possible; if not, the water taken aboard should be treated by adding a teaspoonful of chloride of lime, taken from a freshly opened tin, to each 512 gallons. Whenever practicable, the ship should be brought alongside of the wharf to receive water, as water obtained from water boats is notoriously bad, for even when the water is supplied from a source of unquestioned purity the men on these boats are careless in handling it and pollution results. In many cases if the owners of these boats are not watched they will pump water directly out of a contaminated stream into the tanks of the vessels they are supplying. Everyone on board a vessel should be provided with a separate towel, soap, and drinking cup for his individual use in order to

prevent conveyance of disease from one person to another. Water butts should have spigots and tight-fitting tops secured by lock and key to prevent seamen from dipping their cups into the water.

Every vessel should carry at least sufficient water to provide 6 gallons per day for each seaman and 10 gallons per day for each fireman aboard.

Ice used for cooling water should be clear, natural ice or ice made from distilled water or water certified as aforesaid, and before the ice is placed in the water it shall be first carefully washed with water of known safety and handled in such manner as to prevent its becoming contaminated by the organisms of infectious or contagious diseases. The foregoing does not, however, apply to ice which does not come in contact with the water which is to be cooled.

Mosquitoes.-The ship should be kept free from mosquitoes. Mosquitoes do not, as a rule, go far from land unless blown by the wind, so, if the vessel is to lie at anchor, a site should be chosen that is sufficiently far from the shore to escape them. When the ship is to lie at the dock or close to the shore, the living compartments should be protected by screens or wire netting of 18-mesh wire placed over the portholes, skylights, and ventilators. Closely fitting screened doors, with springs to shut them after being opened, should be provided. Mosquito bars may be used over bunks, but these are nothing like as efficacious as screening. Mosquitoes should be looked for early in the morning and all that are found in the compartments should be killed. They are usually to be found on the screens trying to get out.

Mosquitoes should not be permitted to breed on board. All barrels, water butts, and buckets, and all articles containing water should be kept covered or be screened. A bucket of fresh water without a cover that has been left in an out-of-the-way place and forgotten will provide a breeding place for hundreds of mosquitoes which may remain with the ship during a long voyage if she stays in tropical waters. The water in the bilges of the vessel and in the bottom of lifeboats should be treated with a small quantity of kerosene oil, sufficient to provide a scum over its surface. Wiggle tails come to the surface of the water to breathe and the kerosene forms a film through which they can not pass to get air, and without air they can not live. The oiling should be done at least once a week as long as there are any mosquitoes on board.

Rats come on board ship by way of the mooring lines or gang planks or conceal themselves in parcels or freight. They multiply rapidly, two females having been known to give birth to 180 in a year. They are omnivorous and can maintain themselves for long periods on very little food. They cause great damage to property