The micro-organisms of fermentation practically considered / by Alfred Jörgensen.

  • Jörgensen, Alfred, 1848-1925.
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: The micro-organisms of fermentation practically considered / by Alfred Jörgensen. Source: Wellcome Collection.

    34/198 (page 12)
    tbese poisonous substances must be rletermined in eacb individual case. Since it is probable tbat tbe manipulation of such poisons may act injuriously on tbe workmen, tbe question bas been determined in bow great a state of dilution tbey can be used in Order to act to tbe füllest extent. In Communications to tbe Royal Sanitary Board in 1881, R. Kocb bas given tbe results of a considerable number of investigations of tbis nature wliicli were made from bygienic considerations, Tbe various disinfecting substances were tested for tbeir power of killing spores of bacteria, spores of mould, yeast-cells, and bacteria. For practical reasons, bowever, Kocb at tbe same time endeavoured to ascertain wbat quantity of tbe substance under examination sufficed to stop tbe development of micro- organisms in a favourable nutritive liquid. I give bere in brief, from tbe publisbed researcbes of Kocb, tbe results obtained. Carbolic acid did not prove to be such a superior disinfecting substance as it is generally considered to be. A 6 per Cent, solution destroyed tbe power of development of tbe spores of tbe bacillus of antbrax only after forty-eigbt bours, wbilst tbe Bacilhos anthracis itself was killed in two minutes by tbe action of a 1 per cent. solution. A solution of 1 in 850 sufficed to stop tbe growtb of tbe latter; wetting tbe spores of Bacillus anthracis five to seven times witb a 5 per Cent, solution caused a retardation of tbeir development, oily or alcobolic 5 per cent. solution, carbolic acid was f/ absolutely witbout action on tbe spores of tbis bacillus. In tbe form of vapour, carbolic acid acts more strongly, yet tbe action of carbolic acid vapour at 75° C. for two bours did not destroy tbe power of development of tbe above-mentioned spores. Sulpburous acid is not able, except under very favourable conditions, to lull all germs ; tbe same bolds good for calcium bisulpbite and zinc cbloride. Cblorine, bromine, and corrosive Sublimate (mercuric cbloride) are, bowever, disinfectants certain in tbeir action. Tbe Sublimate, according to Kocb, acts fatally upon all germs in a proportion of 1 in 1,000, in most cases even in 1 in 5,000. Tbis Statement must, bowever, according to tbe new investigations of Joban Olsen, be considerably modified ; Olsen found tbat witb some