View report page

44
peratures. These substances are variously called
disinfectants, antiseptics, and deodorants. The
most ordinary of them, and Nature's own disinfectant,
is the oxygen gas of the atmosphere. In the form
of ozone, which exists in all pure atmospheres, it
attacks decomposing animal and vegetable matter,
and seems to have the power of oxidising germpoisons
in the air. Hence the importance of fresh
air in rooms at all times, whether disease is present
or not.
Pure water also contains oxygen gas, and the
tendency of water is to destroy all germ-poisons
that are put into it. It constantly happens, however,
that all the oxygen of water is exhausted by the
impurities it contains, and then the water is no
longer capable of disinfecting, but becomes a source
of contamination and the means itself of conveying
poison. We had a familiar instance of this in the
parish of Saint James's, Westminster, in 1854,
when the water from the Broad Street pump became
contaminated with cholera poison, and destroyed
hundreds of persons who drank it, with Cholera. I
examined the water of this pump six weeks after,
and found only minute quantities of organic matter
of any kind. It contained, however, Carbonic Acid
Gas, and Salts of Nitric Acid, which had undoubtedly
been formed by the oxidating agency of the oxygen
in the water, and which was deficient at the time
of the Cholera poisoning, from the excess of organic
matter, and deficiency of oxygen gas.
Some of the disinfectants ordinarily recommended