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Case 4*.—" The beds show evidence of careful cultivation, but I was informed that the water
is frequently so dirty that it has to be shut oft from the beds. There is evidence of occasional
contamination due to deposit of human excreta near the intake The effluent from the
sewage farm is discharged into the river about 2 miles above the beds."
Case 5†.—" The beds are situated in meadow land There are two sets of beds,
one of which is supplied entirely by water from deep borings into the chalk. The second set of
beds adjoin the river from which water is directly received. There was evidence of
occasional contamination of the river and the second set of beds from cesspool overflows."
Case 6†.—" The beds lie in a deep hollow, and are supplied with water principally from
a spring rising at the head of the beds, but a ditch on the north side conveys a,quantity of surface
water to the beds. The ground sloping to the beds on either side is cultivated as a market garden ;
in close proximity are piggeries and stables, the drainage from which flows over the ground
towards the beds. The contents of the cesspool are used on the land for manurial purposes."
Case 7§.—" These beds are situated on a market garden and fruit farm. There are two sets
of beds: No. 1 set is supplied with water from a watercourse which is principally surface water
supplemented in time of drought by a little water from borings ; this is used for growing summer
and autu'i n cress. No.2 set of beds is supplied by a series of deep borings into the chalk.
This set is used for the cultivation of spring cress. On the farm, and in close proximity to the
beds, is the septic tank sewage plant of the village. The effluent from th-s plant is allowed
to run into shallow trenches near to, and at a higher level than, No. 1 set of beds, into which it
eventually percolates; or it is run on to the land for manurial purposes in connection with the
cultivation of salads, celery, etc."
Case 8.—" No manure is used on the beds, it is said, but a few cattle graze in the field
around them. On 29th July, 1904, the sides and bed of the river were being cleansed just
above these watercress beds. The water was very dirty, with much floating scum in it.
It was flowing into the watercress beds and I called Mr. 's attention to it, upon
which he closed the intake"
Case 9.—" These beds are low-lying the top beds are supplied partly by spring
water and partly from a ditch. I traced this ditch and found that some of the water was quite
black. I afterwards found that it came from a farm in the immediate neighbourhood, where
cows are kept; the cowshed drains and the whole of the washings from carts and dairy
utensils run into this ditch, and eventually into the watercress bed."
Case 10||.—The beds form part of a sewage farm, and the sewage effluent was by agreement
supplied for the purpose of growing watercress in them. The practice has now been discontinued,
and the beds are not at the present time in use."
The bacteriological enquiry carried out by Dr. Houston strikingly confirms the evidence yielded
by topographical investigation; indeed, he found that four samples, taken from beds the topographical
conditions of which were satisfactory, were at least ten million times purer (bacteriologically) than samples
from two of the beds most open to objection, and at least one million times purer than samples from three
other beds in which the topographical conditions were noted as being unsatisfactory. Dr. Houston
reports that any danger accruing to the consumer of "unwashed watercress is enormously reduced by
careful washing of the cress," but that "even an excess of care devoted to the washing of cress from
polluted sources does not always entirely free the cress from objectionable microbes." He remarks on
the "question of standards" that a bacteriological classification of the affluent waters supplying watercress
beds—a classification which, he suggests, should be based on lines already tentatively brought
forward by him in reports to the Local Government Board and Royal Commission on Sewage Disposal
—would be of value particularly when coupled with the observations of the chemist and topographist.
It is quite clear from the inspectors' inquiries and from Dr. Houston's results that cress of the best quality
can be grown under conditions to which, from a public health point of view, no exception can be taken ;
and, again, having in view the extent to which careful washing eliminates impurity, it may be assumed
that there is under existing circumstances no material risk in consuming the watercress supplied from
the majority of the beds sending watercress into London. Objection must, however, be taken on
topographical, chemical, and bacteriological grounds to certain beds, especially those in class D in the
table on page 5, and effort should be made to prevent the consumption of watercress from these beds
in their present condition.
To this report is appended the reports of Dr. Clowes, the Council's chemist, and of Dr. Houston,
who has made bacteriological examination of samples of water and of watercress.
Shirley F. Murphy,
Medical Officer of Health.
Puhlic Health Department,
8, St. Martin's Place,
23rd March, 1905.
* Sample of water XI. (Table I.) was taken from these beds for bacteriological examination,
4 Sample of water V. (Table I ) was taken from these beds for bacteriological examination.
‡ Sample of tprlug water VI. (Table I.) was taken from these beds for bacteriological examination.
§ Sample of water X. (Table I.) was taken from these beds for bacteriological examination.
||Sample of water III. (Table I.) was taken from these beds for bacteriological examination.