Two gases are available for use in disinfection, and these are valuable particularly in killing germs left in a room after a patient suffering from an infectious disease has been removed. The diseases referred to in the following chapters are all of this nature, and one of these two gases ought to be used in every case; otherwise the room may continue to harbor germs of the disease for months or years with the possibility of infecting a future tenant at a time when his vitality was such as to make him an easy prey. Nor must the contents of the room be overlooked.
The writer was recently told of a large family where one child had scarlet fever, recovering in September. The sick room was thoroughly disinfected, but the careful housewife, fearing damage to her blankets, had taken them to the attic before disinfection began. In the cold weather of February these blankets were brought down, and in six days the two children sleeping under them had contracted the disease.
Sulfur as a disinfectant.
When sulfur is burned, a gas is formed known as sulfurous acid, and until the last few years, it was the most common of all disinfecting agencies. The writer well remembers that when about to visit a city in South America infested with yellow fever, he was seriously advised to fill the inside of his shoes with sulfur as a precaution against the disease. He might as well have worn a red ribbon on his hat so far as any protection went, but it illustrates the confidence formerly shown in sulfur as a disinfectant.
It is now known that in the dry, powdered state, sulfur is of no value unless, perhaps, the germs be smothered with the sulfur flour. When burned, however, the gas given off has a certain disinfecting property, although this is limited. It has almost no power of penetrating into curtains, blankets, and upholstered furniture, although the penetration is decidedly increased if these objects are moistened either by steam or by water vapor. The proper amount of sulfur to be burned for any room is at the rate of 3 pounds per 1000 cubic feet of air space in the room. Thus, if a room be 12 feet by 15 feet and 8 feet high, containing 1440 cubic feet, it would be necessary to burn 144/100 of 3 pounds, or 4-1/3 pounds.
Before undertaking to disinfect a room with sulfur, it should be made thoroughly air-tight, and this must be done carefully, not merely by closing the larger and obvious openings, like doors and windows, but by pasting strips of paper over every crack which might allow air to escape. Thus the four edges of the window sash must be pasted up, and a strip must close the crack between the two sashes. All the doors but the one reserved for exit should be pasted up from the inside, and finally this last door pasted up on the outside. If the floor has settled away from the base-board, the cracks thus made must be pasted up. In short, the room must be made absolutely air-tight. The room should be left thus closed for at least twenty-four hours, and since there is some danger from fire, a proper provision should be made for the burning sulfur. This can be done by placing an old milk pan (a most convenient object in which to burn the sulfur) on a couple of bricks, which may be set inside a wash tub with perhaps three or four inches of water in the tub. The most convenient way of ignition is to moisten the sulfur with a little alcohol which can be readily set on fire.
Since clothes of every sort are more effectually acted upon when moist, they should be sprinkled with a hand atomizer just as the sulfur is lighted, and this should always be done in the case of any stuffed furniture or hangings. Anything that can be removed should be taken out and sterilized by steam, since live steam is the only disinfecting agent which will penetrate such things as mattresses, pillows, and rolled-up bundles of every sort, and with these last even steam is not certain. It is far safer to send a mattress to the cleaner to be steamed than to try to sterilize such bulky objects at home. It requires about twenty-four hours with the room tightly closed to generate enough gas so that the bacteria which may have found their way onto the walls or floor or ceiling or into the air of a room will be surely killed. After that time the room can be opened and then the usual household cleansing processes carried out as an additional safeguard. It is a wise measure in the case of infectious diseases, even after a room has been fumigated with sulfurous gas, to wipe off the woodwork and the walls, if their construction allows it, with a solution of carbolic acid, since in this way the germs which have accumulated on the woodwork will certainly be killed.
Formaldehyde disinfectant.
Formaldehyde is the other gas which is commonly used for disinfecting the air of a room. It is most readily produced by buying solidified formaldehyde and then decomposing it by the action of heat. Formaldehyde candles, as they are called, may be purchased at almost any drug store, and while special forms of generating stoves may be found in the open market, an ordinary heating apparatus of almost any sort will answer the purpose of decomposing the solid formaldehyde. About 20 ounces of the formalin should be used for each 1000 cubic feet of space. With this agent, however, as with sulfur, the penetrating power of the gas is not very great, and such things as mattresses and clothing should be sent to a steam sterilizer rather than be trusted solely to the power of the formaldehyde.
In using this gas, the same care about pasting up cracks and crevices in the room should be followed as already prescribed for the use of sulfur, and, as with sulfur, a reasonable precaution against fire should be taken by placing the apparatus in a tub of water or in a large pan of sand where accidents cannot happen. The room should be kept closed for at least twelve hours, and then should be thoroughly aired, and if the room is to be used again soon, the disagreeable odor may be removed by the free use of ammonia, either sprinkling it around in the room or by placing about saucers of ammonia.