London's Pulse: Medical Officer of Health reports 1848-1972
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Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
London County Council 1899
[Report of the Medical Officer of Health for London County Council]
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VII —ADDENDA.
1.—THE VITALITY OF THE CHOLERA BACILLUS, B. PRODIGIOSUS, AND
STAPHYLOCOCCUS PYOGENES AUREUS IN CROSSNESS CRUDE SEWAGE.
The sewage was not sterilised, as sterilisation greatly alters its chemical composition, and
the object of the experiments was to ascertain broadly whether these germs survive for any length
of time in competition with the numerous other micro-organisms normally present in raw sewage.
(a) Vitality of the Cholera Bacillus in Crossness Crude Sewage.
Experiment 1, October 24th,, 1898.
10 c.c. of Crossness crude sewage were poured into a sterile test-tube, and the tube was
plugged with sterile wool. The contents of the tube were next inoculated with a platinum
loopful of the cholera bacillus taken from a young gelatine culture. The tube containing the.
crude sewage († the cholera bacillus) was kept in a dark cupboard at the room temperature. In
seeking to determine the viability of Koch's vibrio the following plan was adopted. From time to
time a loopful of the sewage was transferred to a tube containing sterile peptone solution (peptone
1 per cent; NaCl 0.5 per cent.). The peptone tube was incubated at 37° C., and in less than
twenty-four hours a loopful of the liquid was taken from near the surface and microscopic stained
cover-glass preparations were made. A number of such preparations were made, and these were
examined microscopically for the presence of Koch's vibrio.
The results obtained are shown in the following Table—
| Date of inoculation of peptone solution. | Date of examination of peptone culture. | Descriptive number of cultures. | Remarks. Results of the examination of the peptone cultures. |
|---|---|---|---|
| 1898. | 1898. | ||
| October 24 (Immediately after the inoculation of the sewage with Koch's vibrio.) | October 25 | (1) | Cholera vibrios present in great abundance and almost in pure culture. |
| October 25 | 26 | (2) | Vibrios could only be found after prolonged searching. |
| „ 26 | 27 | (3) | No difficulty was experienced in finding vibrios. |
| „ 27 | 28 | (4) | Vibrios present in abundance. |
| „ 28 | 29 | (5) | A positive result was with difficulty obtained. |
| „ 31 | November 1 | (6) | „ „ |
| November 1 | 2 | (7) | „ „ |
| „ 2 | 3 | (8) | „ „ |
| „ 3 | 4 | (9) | „ „ |
| „ 4 | 5 | (10) | A doubtfully positive result. |
| „ 9 | 10 | (11) | Only a few vibrios, but these were typical. |
| „18 | 19 | (12) | Many vibrios, but most of them larger (longer and thicker) than normal. |
| „ 24 | 25 | (l3) | ? Positive. |
| December 5 | December 6 | (14) | Quite negative. |
It is to be noted that in culture (1) Koch's vibrio was present almost in pure culture, but in
(2) it was demonstrated only with great difficulty. In (3) and (4), however, vibrios were present
in abundance. In (5), (6), (7), (8), (9) cultures a positive result was arrived at only with great
difficulty, and in (10) the result was only doubtfully positive. In (11) and (12) cultures the
diagnosis was more certain, but in the latter culture the microbe seemed to have become slightly
altered, morphologically. In (13) there was a considerable element of doubt, and in (14) the result
was quite negative.
The apparent rise and fall in the vitality of the vibrio during the progress of the experiment
is of interest.
It is evident that the cholera bacillus is able to exist in Crossness crude sewage in competition
with the numerous other microbes also present and under laboratory conditions of experiment
for a considerable time.
Experiment 2, October 26th, 1898.
The experiment was a repetition of experiment 1, except that a vastly greater number of
cholera germs were added to the sewage, viz., the whole of the surface growth from an oblique agar
culture incubated at 37° C. for three days. Indeed, the number of vibrios added was greatly in
excess of the total number of micro-organisms in the sewage.