London's Pulse: Medical Officer of Health reports 1848-1972

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Bethnal Green 1883

[Report of the Medical Officer of Health for Bethnal Green]

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43
Various other experiments were also made with anthrax spores,
garden earth, etc., and it was shewn satisfactorily that by means of
super-heated steam a maximum temperature of 221° F. was needed to
destroy life, whereas, when hot air was used, 284° F. even did not
produce a satisfactory result.
Three hours were sufficient to disinfect any ordinary bed or bedding-,
but when the article to be disinfected was of special thickness an
interrupted application of the heat was found to be useful. In these
experiments super-heated, but not high-pressure, steam was used;
with this latter one none would have been sufficient.
Steam, also, does not damage articles so much as hot air; colours
fade somewhat, but leather is really the only substance which will not
bear exposure to steam.
Dr. Koch concludes by saying that wherever disinfection by heat is
possible, super-heated steam is to be preferred above all other methods
of disinfection by heat.
! These particulars are extracted from the Report of the German Imperial
Board of Health, vol. i., 1881.
" The result of our experiments with hot air was as follows :—
1. "In hot air bacteria without spores do not survive a temperature of a little
over 212° F.. if continued for an hour and a half,
2. " Spores of mould require an hour and a half at a temperature of 230° F. to
239° F. before being destroyed.
3. " Bacilli spores are only destroyed after three hours at a temperature of
284° F.
4. " Hot air penetrates so slowly into articles to be disinfected that after three
to four hours, at a temperature of 284° F., articles of a moderate size, i.e., a small
bundle of clothes or a pillow, are not disinfected.
5. " The heating of articles for three hours at a temperature of 284° F. damages
them considerably.
(Signed) " Dr. Robert Koch,
"Dr. Gustav "Wolfhugel."
This process of steaming or cooking must be more efficacious than
dry heat; for there exist the three conditions which ensure the desired
object, namely, heat, pressure, and moisture. Moreover, the process
is so rapid that persons bringing their beds and clothing to be
disinfected can have them done while they wait; and this is often
a matter of considerable importance to persons possessing only one
bed, which, if it had to remain in the apparatus a whole night, would
put them to grave inconvenience. The Vestry of St. Mary, Rotherhithe,
use this apparatus, and the Medical Officer, in his answer to
my letter upon the subject, uses the following words:—I am
thoroughly satisfied with the performance of the apparatus. My
disinfection has been a marked success, both as to results and
economy.
With regard to other London parishes: in order to make this report
as complete as possible, I have communicated with every Metropolitan
Medical Officer of Health, and have made inquiries as to the means of
disinfection in his parish. I have tabulated the answers: they are
entered upon the schedule which accompanies this report, and I cannot
refrain from taking this opportunity of publicly thanking those Medical
Officers who kindly supplied me with so much valuable information.