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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In the following pages the chief results as regards (1) total number of bacteria, (2) number
of spores of bacteria, (3) number of liquefying bacteria, (4) number of B. coli, and (5) number of
spores of B. enteritidis sporogenes are tabulated and summarised. Eoth the records contained in
the text of the Second Report and those given in the Addenda A, B, C, D, E, are here dealt with.
The necessity of collecting these figures together, and making brief comments thereon, will
make the summary less concise than it would otherwise have been.
(a) Total Number of Bacteria in 1 c.c.
| Date. | Crossness crude sewage. | Effluent from 4 ft. coke-bed. | Effluent from 6 ft. primary coke-bed. | Effluent from 6 ft. secondary coke-bed. | ||
|---|---|---|---|---|---|---|
| Second Report, Addendum A. Second Report, page 21 | 1898. | 1 | ... | ... | ... | |
| May | 11 | 3,930,000 | 4,800,000 | ... | ||
| 18 | 3,670,000 | 4,100,000 | ... | ... | ||
| 25 | 6.400,000 | 6,100,000 | ... | ... | ||
| June | 9 | 6,500,000 | 1,200,000 | ... | ... | |
| 15 | 4,000,000 | 5,300,000 | ... | ... | ||
| 22 | 9,100,000 | 3,000,000 | ... | ... | ||
| July | 20 | 12,800,000 | 9,200,000 | ... | ... | |
| 27 | 7,200,000 | ... | 6,600,000 | |||
| August | 4 | 4,200.000 | 1,800,000 | ... | ... | |
| 9 | 3,600,000 | 1,700,000 | ... | |||
| 19 | 5,800,000 | 3,400,000 | ||||
| 24 | 4,100,000 | 5,700,000 | ... | |||
| September | 14 | 8,000,000 | 3,400,000 | ... | ||
| 21 | 8,600,000 | 7,200,000 | ... | |||
| 28 | 7,500,000 | 7,500,000 | ... | |||
| October | 5 | 10,500,000 | ... | 8,000,000 | ||
| 12 | 4,000,000 | 4,200,000 | ... | ... | ||
| 21 | 8,000,000 | 15,800,000 | ... | |||
| 26 | 5,200,000 | ... | 3,100,000 | |||
| November | 9 | 7,800,000 | 8,800,000 | ... | ||
| 16 | 5,800,000 | 5,300,000 | ||||
| 23 | 8,600,000 | 4,500,000 | ||||
| 30 | 13,500,000 | 5,400,000 | ... | |||
| December | 7 | 5,600,000 | ' 4,000,000 | |||
| 14 | 19,500,000 | 5,300,000 | ||||
| 21 | 7,400,000 | 6,300,000 | ||||
| Averages ... | 7,357,692 (26 samples) | 4,966,666 (15 samples) | 6,787,500 (8 samples) | 4,300,000 (3 samples) | ||
| Percentage reduct ion (as compared with the raw sewage). | 32 per cent. | 7 per cent. | 41 per cent. | |||
| Average number of bacteria in the raw sewage when the samples were comparative with the samples obtained respectively from the 4 ft., 6 ft. (primary), and 6 ft. (secondary) coke-beds. ✓ * | 6,973,333 j (15 samples cor- ( responding to ( 4 ft. samples. ) | 4,966,666 28 per cent, reduction. | ... | ... | ||
| 6,675,000 ) (8 samples cor-responding to > 6 ft. primary I samples.) | ( 6,787,500 ( slight increase. | ... | ||||
| 11,100,000 \ (3 samples cor- 1 responding to > 6 ft. secondary 4 samples.) / | r 4,300,000 < 61 per cent. (. reduction. | |||||
The table shows that the total number of bacteria in the crude sewage (26 samples), the
effluent from the 4-foot coke-bed (15 samples), the effluent from the G-foot primary coke-bed (8
samples), and the effluent from the 6-foot secondary coke-bed (3 samples) averaged 7,357,692,
4,966,666, 6,787,500, and 4,300,000 per c.c. respectively. The percentage reduction of bacteria in
the effluents being 32, 7, and 41. The average number of bacteria in the 15 samples of crude
sewage corresponding to the 4-foot coke-bed effluents was 6,973,333. In the eight samples corresponding
to the 6-foot primary coke-bed effluents the average was 6,675,000. Lastly, the three
samples of crude sewage corresponding to the 6-foot secondary coke-bed effluents yielded on an
average 11,100,000 bacteria per c.c. Calculated from these figures, the percentage reduction of
bacteria was 28 as regards the 4-foot coke-bed effluents; no reduction, but a slight increase as
regards the 6-foot primary coke-bed effluents, and 61 per cent, in respect of the 6-foot secondary
coke-bed effluents.
As a rule a rise or fall above or below the mean in the number of bacteria in the crude
sewage was associated with a similar increase or decrease of microbes in the corresponding
effluents. Thus, as regards the crude sewage and 4-foot coke-bed effluents, there was a correspondence
in this respect on 11 occasions out of 15; and as regards the raw sewage and 6-foot
primary coke-bed effluents this correspondence was observed in all the eight samples. The records