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the number of liquefying germs and the number of spores. Further, it has been said as regards the
crude sewage, that no distinct parallelism exists between the total number of bacteria and the number
of spores and the relation between the total number and the number of liquefying microbes is not well
marked. Neither, on comparing diagrams 4 and 5, does there appear to be any distinct relation between
the number of spores and the number of liquefying bacteria in the crude sewage.
In order to observe these facts more closely reference may be made to diagrams 6 and 7, which show
the percentage deviation from the mean in the different samples of crude sewage and effluent from the 4-ft.
and 6-ft. beds as regards total number of germs, number of spores, and number of liquefying bacteria.
Firstly, as regards the crude sewage, diagram 6 shows that there is no definite relation between the
total number of bacteria and the number of spores. To some extent, however, there is a relation between
the total number of bacteria and the liquefying germs.
Secondly, as regards the effluents from the coke-beds, diagram 7 shows that there is a distinct relation
between the total number—the number of spores and the number of liquefying bacteria. Although,
however, a rise or fall above or below the mean in the total uumber was nearly always coincident with a
rise or fall above or below the mean in the number of spores and the number of liquefying bacteria, the
percentage deviation in each case showed no parallelism.
Lastly, comparing diagrams 6 and 7, no relationship can be made out between the total number,
the number of spores and the number of liquefying bacteria in the crude sewage, as compared with the
effluent from the 4-ft. bed.
In the first report it was stated (page 4, c. 3) that—"It must not be concluded, however, that
because a micro-organism liquefies gelatine, it will also liquefy all the various and complex kinds of organic
matter existing in sewage. But it is safe to assert that a liquid rich in bacteria of varied species, many of
which are capable of producing liquefaction of gelatine, is likely also to be rich in ability to dissolve solid
or suspended oiganic matter."
As illustrating the complex behaviour of different germs to different albuminoids, and also of the
same organism to different albuminoids, it may be noted that some bacteria liquefy gelatine, others do not;
some coagulate the casein in milk and then dissolve it, others coagulate it and do not further peptonize it,
others peptonize it directly; again some organisms which liquefy gelatine coagulate milk, others coagulate
milk but do not liquefy gelatine; again an organism which liquefies gelatine may or may not produce
liquefaction of fibrin, of blood serum or of egg albumen, and an organism capable of peptonizing fibrin
may fail to liquefy gelatine.
In a description of some of the bacteria found in the crude sewage and in the effluents which
accompanies this report, will be found details relating to their behaviour when grown in milk, gelatine,
blood serum, etc. For example, "sewage proteus" quickly liquefies gelatine and blood serum, and apparently
peptonizes milk without first coagulating it. B. coli produces no liquefaction of gelatine or blood serum,
but clots milk in 24 hours at 37°C. B. mesentericus I. rapidly liquefies gelatine and blood serum, and
apparently peptonizes milk without previous coagulation. B. mesentericus E. liquefies gelatine very slowly,
but liquefies blood serum fairly rapidly at 37°C., and produces a weak clot in milk which appears to be
subsequently dissolved.
In estimating the number of liquifying organisms the following plan* was adopted—The contents of a test
tube containing 10 c.c. of sterile nutrient gelatine were melted and poured into a sterile Petri's capsule. After
the gelatine had become quite solid the surface of the medium was inoculated with 0"1 c.c. of diluted sewage or
effluent (1: 10,000). The diluted sewage or effluent (representing 0.00001 c.c.) was then spread over the entire
surface of the gelatine with a platinum instrument. The plate was next inverted and incubated at 20° C. in this
position until the colonies were sufficiently advanced in their growth for observation. Although this method is
the best one available, it must be remembered that some bacteria liquefy the gelatine so very slowly that they
might readily escape being counted as liquefying germs under the above conditions of experiment. This matters
the less since bacteriologists are in the habit of classing some, at all events, of these bacteria as non-liquefiers.
4.—Spkcies of Micro-organisms present in Crossness Crude Sewage and in the Efflubnts from the
Coke-Beds.
(a) Bacillus enteritidis sporogenes (Klein).†
In the First Report the result of a considerable number of experiments were given, showing that the
spores of B. enteritidis may be present in London crude sewage ‡ in numbers varying from 10 to 1,000 per
c.c. Further, it was pointed out that Dr. Klein's researches tend to show that this organism is causally
related to diarrhoea. That its cultures are extremely virulent may be seen by referring to col. 5, expt. 6,
Table I., and col. 5, expts. 4 and 5, Table II., and also expts. 1 and 2, col. 5, Table I., of First Report. Again,
it was stated that this pathogenic anaerobe is most important from the point of view of the bacterioscopic
analysis of water, and lastly the hope was held out that future work would show what was the fate of
Enteritidis during the nassasre of the sewasre through the biological coke-beds at the Outfall Works.

*See B 5, page 2.—First Report.
+ See figure 2, Plate I., of this report, and Nos. 3 and 14 (Plate I.), First Report.
‡See page 5, and also Table I., of First Report.