Report on chlorine, bromine, iodine, and sulphurous acid as disinfectants / by Dr. Cash.

  • Cash, John Theodore, 1854-1936.
Date:
[1887?]
Catalogue details

Licence: Public Domain Mark

Credit: Report on chlorine, bromine, iodine, and sulphurous acid as disinfectants / by Dr. Cash. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    1/16 (page 425)
    / / No, 4. Report on Chlorine, Bromine, Iodine, and Sulphurous Acid as Act. B No, 4. Disinfectants ; by Dr. Cash, F.R.S. On Chlorine. Bromine, &c, as Disinfectants; From observations of MM. do la Croix and Koch we have already by Dr-Cash* learnt much of the destructive action of halogen elements or their solutions upon the bacillus and spore of anthrax. The information yielded seemed of such great importance as to make a still more extensive examination of these substances desirable. I have therefore carried out an extensive series of experiments with the object of determining the lethal limits of the bodies mentioned, not only with regard to anthrax but to human and bovine tuberculosis. I was further requested by the Local Government Board to extend my observations to sulphurous acid which is already recognised as one of our most efficacious and practical means of disinfection. With the object of rendering the investigation as precise as possible, Method* adopted, I have when testing the effect of solutions of these halogens, employed graduated strengths which could be readily controlled by means of occasional standardising. Water solutions of chlorine lose strength with more or less rapidity, solutions of sulphurous acid rapidly, a partial conversion into sulphuric acid as a result of oxidation taking place. Bromine in solution is moderately stable and iodine practically perfectly so. Using a solution of iodine of known strength as the starting point for the standardising of the other solutions, and taking of it an ~ solution (i.e., 12653 grms. of iodine per 1000 C.C. distilled water, or 1 • 27 per cent.), it is easy to satisfy ourselves that an equal volume of standard hyposulphite of soda solution ^ discharges the colour of the iodine, starch being used as the indicator. The hyposulphite being found up to strength, the standardising of chlorine and bromine solutions are effected by estimating their power of liberating iodine from iodide of potassium, starch being as before used as indicator. Koch places the strength of the solutions of halogens which arrest the development of anthrax bacillus as follows :— Iodine 1 to 5,000 Bromine - - - - - 1 to 1,500 Chlorine - - - - - 1 to 1,500 He further found that spores of anthrax were destroyed in :— Iodine (1 to 7,000) - - - - 1 day Bromine (2%) - - - 1 to 5 days Chlorine (freshly made) - - - 1 to 5 days V F 2