Report of the Departmental Committee apointed to inquire as to precautions for preventing danger of infection from anthrax in the manipulation of wool, goat hair, and camel hair.
- Great Britain. Committee on Anthrax.
- Date:
- 1918
Licence: Public Domain Mark
Credit: Report of the Departmental Committee apointed to inquire as to precautions for preventing danger of infection from anthrax in the manipulation of wool, goat hair, and camel hair. Source: Wellcome Collection.
71/356 page 59
![Note :—The amount.of growth is indicated in the above table as follows :— 4 means abundant growth, apparently more abundant than the growth from control threads after four days. 3, growth about equal to that of control. 2, growth distinctly less than that of control. 1, shght growth. : 0, no growth. (See photograph on previous page.) These results show that at temperatures under 30 °C. 2°5 per cent. formal acts too slowly for practical purposes. At 30° C. a solution of that strength is not fully lethal in half an hour, but 1 is efficient in one hour. At 40° G. an exposure of 15 minutes and at 50° C. an exposure of 74 minutes are sufficient to bring about the death of anthrax spores not protected by associated material, It would appear, therefore, that 2°5 per cent. formal at temperatures under 40° C. does not act rapidly enough to ensure complete disinfection of wool in 20 minutes. The following ‘able gives the result of several sets of experiments made to test the action of formal of three different strengths at approximately the same temperature (39° to 44° 0.) :— Effect of dilution on the action of Formal upon Anthrax Spores. Duration. 1 per Cent. Formal at 2°5 per Cent. Formal 4 per Cent. Formal at 40° C.* at 44°C.§ 39°C. 1 minute - . - = - 5 minutes - = 5 = 4 ce 15 ” ‘4 ou oe KS 4 = 20 ” a os = - = a . eee 60 ce ae 4 5 NES, Se ie 120 = :,, Ms : : “ 2 SOU ie & é : “ . F 3 * Control in water at 40°C. Control in water at 40° C. dipped 3° ‘4 pa cent. ammonia. PRODODOONNNND ee | ooocoo|] Hr elt f ooo | coon For explanation of figures see note to previous table ; — means no observation. * See photograph on previous page. § See photograph opposite page 60. These results taken in*conjunction with those given in the, previous table show, within certain limits, that temperature is of greater importance than the strength of solution of formal ‘as regards lethal action. To obtain fuller information upon this point, experiments with ane ter exposure were made. Lethal action of 1 per cent., 2°5 per cent., and 4 per cent. Solution of Formaldehyde at 40° C. Duration of Exposure. | Control. No Formal. Formal, 1 per Cent. Formal, 2:5 per Cent, | » Formal, 4 per Cent. Vea - - - - 4 4 f}- fy = - - - - 4 4 1 minute - - - 3 pao 2 2 minutes - - - 1 0 0 aos - 0 0 0 de ee - : - 0 0 0 <i - - ) 0 0 0 Consistent as these results appear to be, they cannot be accepted as proving the absolute efficacy of short exposures (see previous table). Thus, in a series of experiments, in which the exposures were made at 50° C.; the following results were obtained with a 1 per cent. formal :— 1 minute 2 2 s - ie - - ore: ¥ minutes 2 2 meee - - - - ee anys ”) 0 ” : cy = bg - x ix Ee re 1 aa Sc keene 802 a RRS oy Controls - = ~ = ae = ~4and3 kk 2](https://iiif.wellcomecollection.org/image/b32178049_0071.jp2/full/800%2C/0/default.jpg)
