Report of the Committee on Disinfectants of the American Public Health Association, 1885.

Date:
1885
Catalogue details

Licence: Public Domain Mark

Credit: Report of the Committee on Disinfectants of the American Public Health Association, 1885. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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    6 cal application of those agents which withstand these tests. In our experiments below reported, the material which has served to test the germicide power of the agents named is 'broken-down beef-tea, exposed in the labo- ratory for several days, and containing a variety of putre- factive bacteria and their spores. The spores of Bacillus suhtilis are also invariably present in this stock, and when a certain agent is successful in destroying all other micro- organisms, we frequently have in our culture-solutions a pure culture of this bacillus, which is noted for its abun- dant and wide distribution, and for the great resisting power of its spores. In order to meet the objection of those who are likely to cavil because no disease germs are present in the material mentioned, a culture of Bacil- lus anthracis containing spores is added to this stock solu- tion. It is well known that anthrax spores constitute one of the most difficult tests of germicide power; not more difficult, however, than the spores of B. suhtilis. We may safely assume, then, that an agent which will destroy these spores will also destroy all known disease germs, and probably all organisms of this class, known or un- known. The micrococci and bacilli not containing spores are far more easily destroyed. The time of exposure to the disinfecting agent in all of these experiments has been two hours. And the amount of material to be disinfected has in every case been made equal to the amount of the solution of the disinfecting agent under trial. Thus to test an agent in the propor- tion of fifty per cent., a certain quantity—10 cc.—of the agent undiluted (100 per cent.) is added to an equal quan- tity of the broken-down beef stock described. If we wish to test the agent in the proportion of four per cent., an eight per cent, solution is made, and this is added to an equal quantity of the stock, etc. The mixture is placed in a wide-mouthed bottle containing 25 cc. and is set aside for two hours. A minute quantity of the material is then introduced into two little culture-flasks * (all ex- *The flasks used are all made in the laboratory, and are of the form described in the chapter on Technology in my hook—Bacteria.