Extracts from the annual report of the medical officer of the Local Government Board for 1884. Disinfection by heat. / being a report by H. F. Parsons.

Parsons, H. F.

Date:: 1886

Credit: Extracts from the annual report of the medical officer of the Local Government Board for 1884. Disinfection by heat. / being a report by H. F. Parsons. Source: Wellcome Collection.

Provider: This material has been provided by London School of Hygiene & Tropical Medicine Library & Archives Service. The original may be consulted at London School of Hygiene & Tropical Medicine Library & Archives Service.

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$3.— With Spores of an old Culture of Bacillus Anthracis. (a.) On flannel for 1 hour,'l guinea-pig (b.) On flannel for ^ hour ditto (c.) On flannel for | hour ditto (d.) On flannel for 5 minutes ditto ^Remained well. Had swelling at seat of inoculation 6 days after, but remained well. On Disinfection l>y Heat; by Dr. Parsons. With spores. B.—Experiments with artificial Cultures of Uacillus of Swine Fever. (a.) On flannel for 5 minutes, inoculated 2 mice and 1 rabbit h On swine fever, (l.) Ditto \ hour ditto ditto - I All animals (c.) Ditto ^ hour ditto 1 rabbit - > remained (d.) Ditto 1 hour ditto 1 ditto - j well. (e.) In capillary tube for 1 hour ditto 1 ditto - ) C.—Experiments icith Tuberculous Pus from Guinea-pig exposed to Steam. Remained well Feb- On tubercle. ruary7th, 1885. Died on July 25 th, 1884, from un- known cause, not tubercle. (d.) For 1 hour ditto ditto -1 Remained well Feb- (c.) For 1 hour iu capillary tube ditto ditto - J ruary 7th, 1885. The results of the above experiments are conclusive as to the destructive power of steam at 212° F. upon all the contagia submitted to its action ; in one instance only was there room for suspicion that the disinfection had not been complete; this was in the case of the highly resisting anthrax spores, exposed to steam for five minutes only. On the other hand, the animals inoculated with unheated portions of the same materials all died. These results are in accordance with those of Koch, Gaffky, and Lofflcr, and it may be considered established that the complete penetration of an object by steam heat for more than five minutes is sufficient for its thorough disinfection. In view of the above satisfactory results it was not deemed necessary to make any experiments as to the disinfecting power of steam at higher temperatures or under pressure ; its efficacy may be taken for granted. (a.) For 5 minutes on flannel, 1 guinea-pig - *] (inoculated June 25th, 1884) - > (b.) For A hour ditto ditto - J (c.) For ^ hour ditto ditto Experiments on Lice. In view of the frequent employment of heat for the destruction of On lice, vermin in clothing, it was thought desirable to make some observations on this point in connection with the present inquiry. It is easy to recognize when the adult insects have been destroyed ; they become shrivelled and motionless, and relax their grasp, so as to$