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Disinfection

the act of purifying from infectious and contagious matter.

Agents which can destroy the specific poisons of infectious diseases and prevent them from spreading are called disinfectants. The action of disinfectants is therefore analogous to that of antiseptics, and conists of the destruction of low forms of life.

Thermal and chemical means are used in disinfection. Hot air and steam are included in thermal disinfection, while chemical disinfection destroys the infective particles by applying substances of a chemical nature. Heat, and especially fire, is the best disinfectant. Clothing which can be boiled without injury is thereby deprived of infectious germs.

When heat cannot be applied, gaseous or liquid disinfectants are used. Cold is a natural disinfectant. The first frost kills an epidemic of yellow fever; but a temperature of zero does not kill the infection of anthrax, typhoid, tuberculosis, or smallpox. Most large European cities have disinfecting stations under the direction of the health authorities. Disinfecting ovens are now replaced by cylinders or chambers, into which steam at a temperature of 220° to 230° F. with a pressure sufficient to prevent any disposition to moisture in the chamber should be so admitted as to drive out all air from the interstices of the infected articles, as well as from the chamber, thus insuring penetration into the interior.

Among the most important disinfectants for practical purposes are chlorine, carbolic acid, sulphurous acid, Condy's green and red fluids, containing respectively manganate and permanganate of potash, and Burnett's fluid, containing chloride of zinc. Carbolic acid is one of the most effective, needing, however, some care in the handling, as it sometimes causes severe burns. As a deodorizer carbolic acid is not so energetic as chlorine and permanganate of potash; but there is this great difference, that while the acid destroys organic substances which give rise to offensive odor, the others mainly attack the odor DISMAL SWAMP itself and therefore require to be applied frequently if perfect sweetness is desired. The vapor of carbolic acid is not a disinfectant at ordinary temperatures, as bacilli are not destroyed, even when exposed to it for six weeks. It is therefore evident that the mere exposure of that substance in vessels is of no service in disinfecting a room. Sulphurous acid has long been in repute, both in the form of solution and in the gaseous state. Recent experiments on cultivated bacilli seem to prove that, while in the liquid state it is a powerful dsinfectant, it has little action either as dry gas or along with watery vapor.

Of all the long list of popular disinfectants, chlorine, bromine, iodine, osmic acid, potassium permanganate (Condy's fluid), and corrosive sublimate seem to be the most certain and rapid in their action, but all of these are more or less open to objection. For application to the skin Condy's fluid is one of the readiest preparations. In cases of contagious or infectious disease, disinfectants such as chlorinated lime or carbolic acid should be used at once, being placed about the house, especially in the sick room and in the passages and landing outside of it. Every article of clothing and furniture should be carefully treated, as the germs may lurk in them and break out after a lapse of months or years.