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E.—DESCRIPTION OP MICRO-PHOTOGRAPHS ACCOMPANYING THE REPORT.
Photo. 1.—Phenol (0.05 %) gelatine surface plate cultivation of diluted Crossness crude sewage.—
Natural size. 0.1 c.c. of a 1 in 10,000 dilution of Crossness crude sewage. After two days
incubation at 20° C. 75 colonies counted in all. 15 of these were typical of B. Coli Communis, and
could not be distinguished from it by a careful naked-eye examination, when magnified with a hand
lens, and when viewed under a low power of the microscope. Microscopic preparations looked at
under a high power showed similar cells in each case. Possibly some among them showed rods
slightly longer and possessed of rather more decided movement than the true B. Coli, yet on the
whole the appearances were such as to suggest a similarity and to lead to the belief that the colonies,
one and all, were those of B. Coli Communis. Sub-cultures from these colonies (1 to 15 inclusive)
were made in "gelatine-shake" for gas production, in litmus milk for acidity and clotting, and in
broth for diffuse cloudiness and indol reaction.
Gelatine-shake cidtures. 1 to 15 inclusive produced gas in less than 24 hours. Thus it may
be said that in this sample of crude sewage there were present, out of a total of 7½ million bacteria,
1,500,000 gas-producing coli-like germs per c.c. On the seventh day (at 20° C.) there was no sign
of liquefaction of the gelatine in any of the tubes.
Litmus milk cultures. By the sixth day (at 37° C.) 6 and 10 strongly acid (6 commencing
clot, 10 solid clot); 9 and 11 practically no change; 2, 8, 12 and 13 slightly acid; 1, 3, 4, 5, 7, 14
and 15 very faintly acid. Thus in this sample of crude sewage there were present 1,500,000 gasforming
coli-like germs per c.c. Of these 100,000 possessed the power of turning milk strongly acid
and of forming a solid clot, 100,000 produced strong acidity and showed delayed clotting ability,
200,000 gave rise to no visible change in milk, 400,000 turned the milk slightly acid, and 700,000
produced traces of acid.
Broth cultures. After one day's growth at 37° C. diffuse cloudiness appeared in all the tubes.
Later, some of them showed a slight scum on the surface. On the 6th day (at 37° C.) all the tubes
were tested for indol reaction and all gave a negative result with the exception of 6, which showed a
strong indol reaction. Thus, out of 1,500,000 gas-forming coli-like germs per c.c. of sewage, only
100,000 possessed the power of forming indol.
Photo. 2.—Gelatine plate culture of diluted Crossness crude sewage.—Natural size. 1 c.c. of
diluted Crossness crude sewage (1 : 10,000). After two days' incubation at 20° C., 402 colonies were
counted, this corresponds to 4,020,000 germs per c.c. of sewage. From one of Dr. Klein's negatives.
Photo. 3.—Bacillus Enteritidis Sporogenes.—Preparation from serum culture showing spores,
x 1,000. It has been already shown that the spores of this anaerobic micro-organism may be present
in London crude sewage in numbers varying from 100 to 1,000 per c.c.
Photo 4.—Bacillus Coli Communis.—Gelatine plate culture, natural size.
Photo. 5.—Bacillus Coli Communis.—" Gelatine shake" cultures, showing numerous gas
bubbles after 24 hours' growth at 20° C. Natural size.
Photo. 6.—Bacillus Coli Communis.—Preparation from agar cultivation, one day's growth,
x 1,000. There are usually more than 100,000 germs of Bacillus Coli Communis per c.c. of London
crude sewage.
Photo. 7.—Bacillus Mycoides.—A single colony growing in agar, about natural size. In some
samples of London crude sewage there are 10 spores of this bacillus present per c.c.
Photo. 8.—Bacillus Mycoides.—Impression preparation from a gelatine plate, x 1,000.
Photo. 9.—Bacillus Mesentericus.—Preparation from an agar culture showing rods,rods containing
spores, and free spores, x 1,000. There are several varieties of Bacillus Mesentericus present
in London crude sewage. 10 to 20 spores per c.c. is a number commonly found.
Photo. 10.—Bacillus Megaterium.—Preparation showing spores, x 1,000, occasionally found in
London crude sewage.
Photo. 11.—Bacillus Subtilis.—Preparation from an agar culture, showing spores, x 1,500. The
spores of this micro-organism are frequently found in London crude sewage. There may be as many
as 10 to 20 spores present per c.c. of sewage.
Photo. 12.—Proteus vxdgaris.—Impression preparation from a gelatine cultivation x 1,000.
This, although the type of the putrefactive protean species, is not the form most commonly found in
London crude sewage. The proteus most abundant in London crude sewage has rods much shorter
than the typical proteus vulgaris, and indeed more closely resembles the bacterium termo as
originally described by Dujardin, and which at that time was supposed to be the sole cause of
putrefaction.
Photo. 13.—Bacillus Coli Communis.—Surface colony in gelatine plate, x 8.
Photo. 14.—Bacillus Enteritidis Sporogenes.—Growth in anaerobic milk-cultures, about
natural size.
Prank Clowes,
Chemist.
40, Craven-street, W.C.,
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