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.

    42/162 (page 24)
    a continuous flow of minute bubbles from the interior of the liquid to its surface. Tested upon broken-down beef- tea, when the proportion of H-O. was 3.98 per cent, (say 4 per cent.), the solution was found to be active in the proportion of 3D per cent., while it failed in the propor- tion of 20 per cent. ; that is to say, 1.2 per cent, of H»0, in two hours' time destroyed all of the organisms present in the broken-down beef stock, and 0.8 per cent, failed to do so. Tested upon a pure culture of B. anthracis con- taining spores, the same solution was effective in 20 per cent. (0.8 per cent. H,0,, = 1:125), and failed in 10 per cent. Tested upon a pure culture of a micrococcus, ob- tained from a drop of blood drawn from the inflamed area in a case of vaccinal erysipelas, the same solution was effective in the proportion of 10 per cent. (0.4 per cent, of HiOa = 1:250), and failed at 5 per cent. In ex- periments made at a later date (March 28th) when the strength of the solution was reduced to 2.4 per cent., Mi- crococcus tetragemis was destroyed by 10 per cent. (0,24 per cent. H,0, = 1:400), while the same amount failed to destroy the vitality of the micrococcus of pus—pure cul- ture obtained from an acute abscess—showing a difference in t^e resisting power of these two organisms. As the solution used in these experiments contained five per cent, of sulphuric acid, which in a previous se- ries of experiments* has been shown by the writer to be fatal to the micrcoccus of pus in the proportion of 1:200, it is evident that a failure to destroy the vitality of the same micrococcus in 1:400 does not give this solution any very notable advantage over a simple aqueous solution of sulphuric acid. The germicide power of the solution used, as tested by its action upon spores, is, however, consider- ably above that of sulphuric acid alone. Dr. Duggan has ascertained that to destroy all of the organisms in broken- down beef-tea requires 8 per cent, of H..SO1, whereas 30 per cent, of our solution of H-iO^;, containing 5 per cent, of sul- phuric acid (= 1.5 per cent, of H-^SOi), is effective. These experiments indicate that unless chemists can