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54
II.—THE EXPERIMENTS ON BACTERIAL TREATMENT AT BARKING.
It will be remembered that in the First Report the results were given of the examination of
nine samples of Barking crude sewage. In the Second Report the results of the bacterial treatment
of the sewage in coke-beds at Crossness were given. Here it is proposed to deal with somewhat
similar experiments carried out at Barking.
I.—THE COKE AND RAGSTONE BEDS. *
The beds were four in number, namely, two of coke (coarse and fine), and two of ragstone
(coarse and fine).
Some of the experiments with the effluents as regards their effect on animals are recorded
elsewhere (experiments on animals, p. 68), and it will be remembered that the Supplement to the
Second Report dealt chiefly with the deposit accumulating upon the coke in the coke-beds at
Barking.
The effluents were chiefly examined for the presence of B. enteritidis sporogenes, and the results
obtained in this direction are given in the form of a Table. But on March l6, 1899, a sample of
Barking crude sewage, and the effluents from the fine ragstone-bed and the fine coke-bed were further
examined for the total number of bacteria and number of B. coli. The results were as follows: —
Barking crude sewage 10.000,000 bacteria in 1 c.c. 600,000 B. coli in 1 c.c.
Effluent from fine ragstone-bed 4,000,000 bacteria in 1 c.c. 500,000 B. coli in 1 c.c.
(60 per cent. reduction.) (16 per cent. reduction.)
Effluent from fine coke-bed 1,800.000 bacteria in 1 c.c. 300,000 B. coli in 1 c.c.
(82 per cent. reduction.) (50 per cent. reduction.)

The sign + signifies the presence and the sign — the absence of the spores of B. enteritidis
sporogenes.
These results are shown in graphic form in Diagram 1.
It might have been anticipated that the fine beds would have produced a significant alteration
in the number of spores of this pathogenic anaerobe. Such, however, was not the case, and
although the number in the effluents was usually less than in the corresponding samples of crude
sewage, the reduction was not very well marked, and was not, moreover, a constant feature.
There did not seem to be any striking difference between the coarse and fine beds, or between the
two kinds of material (coke and ragstone) as regards the number of spores of B. enteritidis.
2.—THE DOUBLE COKE-BEDS.
These coke-beds are known as—
The primary coarse coke-bed, series A
The secondary „ „ ,, A description of these beds will be found in
The primary ,, „ „ B the Chemical Division of the Report.
The secondary fine „ „ J
From October 16, 1899, to January 17, 1990, the new beds at Barking were under bacteriological
observation.
The results obtained will be dealt with briefly as follows—
(a) Total Number of Bacteria (gelatine at 20° C.).
The number of micro-organisms in the crude sewage and effluents is given in the following
Table—
* A description of these beds will be found in the Chemical Division of the Report.