Mercurial compounds have been employed as disinfectants since the beginning of bacteriology. Indeed, for a long period mercurial compounds, such as bichloride of mercury, headed the list of chemicals which were thought to be effective in the killing of microorganisms. This perhaps may be attributed to the favorable publicity which Koch¹ in 1881 gave to bichloride of mercury during his work with the organism causing anthrax. In substance he stated that, without special preparation of the objects to be disinfected, bichloride kills by a single application of a very dilute solution, and in a few minutes even the most resistant forms of the organisms are killed.

Geppert² in 1889 first pointed out that false inferences were drawn that bacteria were killed by the action of bichloride of mercury when growth of the organisms was prevented by traces of the chemical in the culture medium. In support of his