This word should only be used to indicate some process or chemical agent which will absolutely kill germs and spores. It is, however, unfortunately applied to other classes, the antiseptics, which will only stop the growth of the germs, but will not kill them; and the deodorants, which merely remove disagreeable smells, and often have no action whatever on the germs themselves. It is obvious that we must use a true disinfectant if we wish to prevent the spread of disease.

Deodorants are such substances as the vapors of turpentine, burning peat, or boiling tar; such liquids as Condy's fluid, or various odorous fluids such as eucalyptus; and such solids as charcoal or camphor. Most of these take away unpleasant smells, but are otherwise useless.

Antiseptics include such bodies as borax, boracic acid, chloride of lime, thymol, Condy's fluid, and various patent disinfectants (so-called). These will arrest the growth of germs, and so prevent putrefacfaction, but few of them will absolutely kill germs. Condy's fluid will, of course, do so, but only when used in such a strong solution that it would discolor and destroy any clothes put into it.

True disinfectants are of three kinds: fumigation, heat, and chemical.

Fumigation by chlorine and sulphurous acid gas. It is probable that many spores will resist this method, and germs hidden, say in the pocket of a coat, will escape destruction.

Heat.

This is the best method of disinfection as, if the temperature is sufficiently high, all germs and their spores will be destroyed. Unfortunately, it cannot be applied in the case of all infected articles. A ready method of heat-disinfection which can be used in every household is, where possible, to boil any infected article, as it has been shown that by boiling for ten minutes all germs and spores are destroyed.

Chemical Disinfectants.

Although there are many so-called disinfectants offered for sale, yet only a few are true disinfectants if used in a strength which will not destroy the articles to be disinfected. Of these we shall only mention two, namely, carbolic acid and corrosive sublimate. Both of these are dangerous poisons, and must be handled with the utmost care. Carbolic acid needs to be diluted in the proportion of 1 part acid to 20 parts water. Corrosive sublimate is sold in the form of tablets, colored blue to avoid accidents. These must be dissolved in water in the proportion of 1 part to 1,000.