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
Barnet 1938
[Report of the Medical Officer of Health for Barnet Urban District Council]
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WATER SUPPLY,
The water for the district is supplied "by the Barnet District
Gas and Water Company and the Colne Valley Water Company.
With regard to the Barnet District Gas and Water Company
all the water is chlorinated; a pathological staff is maintained,
one of whom is a B.Sc., trained under Dr. Beale. The
bulk of the water is examined daily and each pumping station
once a week.
The Colne Valley Water Company exercises constant supervision
and members of the staff are on duty day and night
throughout the year, examining samples. All the water supplied
by this Company is chlorinated.
ANALYSIS.
Report on the Chemical Analysis of Water taken from a Domestic Tap.
| Stated Grains per Gallon | as Parts per 100,000 | |
|---|---|---|
| Total Dissolved Matter left on Evaporation and Dried at 238 Fahr. | 25.48 | 36.40 |
| Loss on Incineration of Residuc | 2.24 | 3.20 |
| Chlorine in Chlorides | 1.60 | 2.29 |
| Equal to Sodium Chloride | 2.64 | 3.77 |
| Nitrogen in Nitrates | 0.29 | 0.41 |
| Free (actual or saline) Ammonia | .001 | .001 |
| Albuminoid (organic) Ammonia | .001 | .001 |
| Oxygen absorbed by Oxidisable Organic Matter etc., from a solution of Potassium | ||
| Permanganate at 80° Fahr. | ||
| In 15 Minutes | .020 | .029 |
| In 4 Hours | .040 | .057 |
| Appearance in 2 feet Tube | Clear | |
| Hardness before Boiling | 20 degrees. | 28½ degrees. |
| " after Boiling | 6½ degrees. | 9½ degrees. |
Result of Bacteriological Examination: Satisfactory.
Total Colonies developed from 1 ctibic centimetre
in plate culture at ordinary temperature 150.
Ditto in bile salt agar plate culture (special
medium for B. coli and its congeners ) nil.
MicConkey broth culture test for B. coli and its
congeners also gave negative result in as much
as 50 cubic centimetres.
The results of chemical analysis are equally satisfactory.