Hints from the Health Department. Leaflet from the archive of the Society of Medical Officers of Health. Credit: Wellcome Collection, London
[Report of the Medical Officer of Health for Greenwich Borough]
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Source of supply | BEFORE TREATMENT | AFTER TREATMENT | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Number of samples | Agar plate count per ml. | Coliform count | Escherichia coli count | Number of samples | Agar plate count per ml. | Coliform count | E. coli count | |||||
20-24 hours at 37°C. | 3 days at 22°C. | Per cent, samples negative in 100 ml. | Count per 100 ml. | Per cent, samples negative in 100 ml. | Count per 100 ml. | 20-24 hours at 37°C. | 3 days at 22°C. | Per cent, samples negative in 100 ml. | Per cent, samples negative in 100 ml. | |||
Thames-derived, | 8,259 | 31.9 | — | 37.91 | 17.3 | 53.58 | 4.7 | 3,710 | 8.0 | — | 99.92 | 99.97 |
Bexley Well | 269 | 0.0 | 12 | 99.26 | — | 100.0 | — | 253 | 0.1 | 46 | 99.60 | 100.0 |
(a) Cray ford No. 1 | 151 | 0.1 | 52 | 92.72 | 0.3 | 96.69 | 0.1 | 254 | 0.5 | 10 | 100.0 | 100.0 |
(b) Cray ford No. 2 | 148 | 0.1 | 131 | 83.78 | 4.9 | 88.51 | — | |||||
(c) Crayford No. 3 | 102 | 0 .0 | 5 | 97.06 | 0.1 | 98.04 | — | |||||
Darenth Well | 244 | 0.1 | 15 | 100.0 | — | 100.0 | — | 250 | 0.0 | 1 | 100.0 | 100.0 |
Deptford Well | 247 | 0.0 | 5 | 98.79 | — | 100.0 | — | 250 | 0.0 | 19 | 100.0 | 100.0 |
(a) Wansunt Borehole | 223 | 0.3 | 31 | 99.10 | — | 100.0 | — | 237 | 0.1 | 89 | 100.0 | 100.0 |
(b) Wansunt Well | 203 | 1.0 | 50 | 99.56 | — | 100.0 | — | |||||
Wilmington Well | 248 | 0.7 | 43 | 98.79 | — | 100.0 | — | 253 | 0.1 | 20 | 99.60 | 100.0 |