Acidum Boricum is a feeble deterrent of germ growth. It is advantageously employed as a collyrium and in douches.

Aqua Hydrogenii Dioxidi is a useful disinfectant on surfaces and in freely flush-able cavities. It acts through disengagement of free oxygen.

Oleum Eucalypti is a mild inhibitor of germ growth. Its use as a spray is thought to lessen scarlatina complications.

Cupri Sulp as, 1-1 million, is used to destroy algae in the reservoirs of drinking water.

Argenti Nitras (0.5% sol.) is a valuable antiseptic and gonorrheal prophylactic when used (once only) as a collyrium in new-born infants. It acts by coagulating albumin.

Balsamum Peruvianum is an efficient germicide in pediculosis pubis; and a mild antiseptic and stimulant in sluggish granulations.

Cresol is an antiseptic of the phenol series, acting by precipitation of protein.

Liquor Formaldehydi is a powerful germicide and disinfectant, acting, presumably, by uniting with the amino group in the proteins of the microbes.

Hexamethylenamina is a urinary antiseptic, acting through the formaldehyde liberated.

Phenol is germicide and disinfectant, being a poison to all protoplasm.