4904

Class I. Positive disinfectants that quickly destroy or completely restrain every contagious and infectious virus.

This class comprises the caustic acids, the acid salts of metals (soluble oxide salts), such as sulphate of iron, sulphate of zinc, etc., carbolic and cresylic (impure carbolic) acids; which not only destroy every communicable virus of disease, but also prevent those kinds of fermentation and decay that aid in propagating epidemics. Frost destroys some infections, but preserves many others, while boiling or high steam heat destroys all contagious matter. It will be observed that no one of these agents, singly, is applicable to every thing and every place that may require disinfection.

Class II. Antiseptics, comprising chemical agents that arrest, or wholly prevent fermentation and decay. See Antiseptics.

This is a large class, and embraces carbolic and salycilic acid, and most of the agents of the first class; but not every antiseptic substance or gas (common salt, or chlorine, for example) can absolutely prevent the fatal operation of epidemic infection.

Class III. Deodorants, absorbents, etc., comprising all the chemicals that deodorize, or destroy putrid exhalation, or that absorb moisture and gases.

Charcoal, quicklime, and chlorine are good examples of this group.