Disinfectants.
400. Disinfectants, Antiseptics, and Deodorants. The word disinfectant is synonymous with the term bactericide or germicide. A disinfectant is a substance which destroys infectious material. An antiseptic is an agent which may hinder the growth, but does not destroy the vitality, of bacteria. A deodorant is not necessarily a disinfectant, or even an antiseptic, but refers to a substance that destroys or masks offensive odors.
401. Air and Water as Disinfectants. Nature has provided for our protection two most efficient means of disinfection,—pure air (sec. 218) and pure water (sec. 119). The air of crowded rooms contains large quantities of bacteria, whereas in pure air there are comparatively few, especially after rain, which carries them to the earth. Living micro-organisms have never been detected in breezes coming from the sea, but in those blowing out from the shore large numbers may be found.
In water tainted with organic matter putrefactive bacteria will flourish, whereas pure water is fatal to their existence. Surface water, because it comes from that part of the soil where bacteria are most active, and where there is most organic matter, generally contains great quantities of these organisms. In the deeper strata of the soil there is practically no decomposition of organic matter going on, hence, water taken from deep sources is comparatively free from bacteria. For this reason, deep well water is greatly to be preferred for drinking purposes to that from surface wells.
402. Disinfectants. It is evident that air and water are not always sufficient to secure disinfection, and this must be accomplished by other means. The destruction of infected material by fire is, of course, a sure but costly means of disinfection. Dry heat, steam, and boiling water are valuable disinfectants and do not injure most fabrics. These agents are generally used in combination with various chemical disinfectants.
Certain chemical agents that are capable of destroying micro-organisms and their spores have come, of late years, into general use. A form of mercury, called corrosive sublimate, is a most efficacious and powerful germicide, but is exceedingly poisonous and can be bought only under restrictions.[[54]] Carbolic acid, chloride of lime, permanganate of potash, and various other preparations made from zinc, iron, and petroleum, are the chemical disinfectants most commonly and successfully used at the present time. There are also numerous varieties of commercial disinfectants now in popular use, such as Platt’s chlorides, bromo-chloral, sanitas, etc., which have proved efficient germicides.