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
Woolwich 1920
[Report of the Medical Officer of Health for Woolwich]
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54
Thursday (4th Nov.).—Of the 1,632 baits left the
previous evening, 616 baits had been removed;
1,602 baits were left that evening.
Friday (5th Nov.).—Of the 1,602 baits left the previous
day, 432 baits had been taken, and these
were replaced. There were 1,602 baits left.
Saturday (6th Nov.).—Only 54 manholes were
examined. Of the 1,288 baits left the previous
evening in these manholes, 258 baits had been
removed. These were replaced. There were 1,628
baits left by midday.
Monday (8th Nov.).—Of the 1,628 baits, 446 baits
had disappeared. In 12 manholes the baits were
not touched throughout the week.
It will be seen from the above particulars that the following were the percentages of the baits that were removed by the rats from the total number of baits .laid:—
| Tuesday, 2nd November | 70% |
| Wednesday, 3rd November | 36% |
| Thursday, 4th November | 37% |
| Friday, 5th November | 27% |
| Saturday, 6th November | 20% |
| Monday, 8th November | 21% |
No manholes were opened on the Sunday.
From a circular prepared by the Ministry of Agriculture
and Fisheries, it would appear that the lethal
(or fatal) dose of Barium carbonate for rats is 6 grains.
The baits laid in the sewers in actual fact contained approximately
11 grains, so that if Barium carbonate has the
efficacy which is claimed for it, a large number of rats must
have been killed in the sewers during the week.
I think, therefore, that this experiment shows that the
laying of poison baits in sewers is justified. I do not