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Broth cultures.—Grows very rapidly at 37° C. The cloudiness throughout the medium is flocculent
rather than diffuse. An abundant white bacterial deposit collects at the foot of the tube. On the surface a skin
is formed, which sinks on shaking the tube, but is re-formed in one night.
Indol formation.—Forms no indol in broth cultures.
Litmus milk cultures.—In 24 hours, at 37° C., the milk has become slightly discoloured; later, a weak
gelatinous clot is formed, and the medium turns faintly acid.
Potato cultures.—The growth is not characteristic; a dirty, faint yellowish-grey coloured growth in 24 hours
at 37° C.
Blood serum cultures.—A granular greyish-white film is formed. Only very slight liquefaction occurs, even
in old cultures.
Reduction of nitrates.—Great reduction of nitrates to nitrites in one night at 37° C. (Bouillon 5 per cent.
KNO3 0.1 per cent).
Remarks.—This organism does not appear to resemble at all closely the descriptions of any of the bacteria
found in sewage and elsewhere. On account of its spreading, film-like character of growth, it has been termed
B. membraneus patulus.
9.—Bacillus Capillareus.
[An aerobic, non-chromogenic, rapidly liquefying, spore-forming (?), motile bacillus.]
Source.—Crude sewage and effluents from coke beds.
Optimum temperature.—Grows luxuriantly at 37° C., also at room temperature.
Morphology*—A large bacillus, forming long chains.
Spore formation.—Old cultures resist heating to 80° C., and this microbe commonly occurs in cultivations
made from sewage which have previously been heated to 80° C. for 10 minutes. A satisfactory double-stained
preparation, however, has not been obtained.
Motility.—This organism is motile.
Gelatine plates cultures.†—The colonies in the depth have a characteristic fluffy appearance. They rapidly
increase in size, and reaching the surface quickly liquefy the gelatine. The growth is filamentous in the depth,
and on the surface from the spreading edge of the colonies, delicate film-like processes are given off, which extend
over the surface of the medium to form irregular patterns. Later, the finer details of growth are lost, owing to
the rapid liquefaction of the gelatine, the colonies eventually appearing as large, more or less circular, areas of
liquefied gelatine with greyish-white contents.
Agar "streak" cultures.—In 24 hours an opaque-white growth of limited extent appears, which along the
spreading edge is slightly transparent and granular-looking. Later, the growth may extend laterally to cover
a wide extent of surface.
Gelatine "streak" cultures.—A longitudinal furrow appears due to the liquefaction of the gelatine, but from
the edge of the furrow delicate processes may be seen extending in irregular fashion over the surface of the solid
gelatine. The furrow is nearly clear as the bacteria slip down the sloping surface with the liquid gelatine, and
collect at the foot of the tube. Soon all details of growth are lost, owing to the progressive liquefaction of the
medium.
Gelatine "stab" cultures.—Liquefaction takes place in funnel form, and extends down the stab to an extent
varying in different cultures. Along the line of the inoculation feathery processes are given off, which extend
into the solid gelatine for a short distance. The masses of bacteria gradually sink to the foot of the liquefied
medium.
Liquefaction.—Liquefies gelatine rapidly, blood serum less rapidly.
Gas formation.—No gas is formed in gelatine "shake" cultures. Sometimes the colonies in "shake"
cultures have a beautiful star-shaped appearance, but at other times they are globular.
Broth cultures.—In broth at 37° C. there is diffuse cloudiness with flocculent masses scattered throughout
the medium. Later, a skin forms on the surface, and an abundant white bacterial deposit collects at the foot of
the tube, leaving the liquid above fairly clear.
Indol.—No indol is formed in broth cultures.
Litmus milk cultures.—No decided change, even after 72 hours at 37° C. In five days weak gelatinous clot,
but no apparent acidity.
Potato cultures.—By the second day at 37° C. a fairly abundant creamy coating has formed on the surface of
the medium, and later this becomes of a dirty-brown colour.
Blood serum cultures.—By the second day, at 37° C., a white-coloured growth, having no special characters.
Liquefaction slowly sets in, and by the 16th day is practically complete.
Reduction of nitrates.—Reduces nitrates to nitrites.
Remarks.—This microbe has been called B. capillareus because of the hair-like character of its growth in
gelatine plate cultures. It resembles in some respects B. mycoides, B. subtilis and B. mesentericus, but not
sufficiently to suggest a similarity of species.
VI—DESCRIPTION OF MICRO-PHOTOGRAPHS AND DIAGRAMMATIC
DRAWINGS ACCOMPANYING REPORT.
Fig. 1.—Proteus vulgaris; impression preparation from "swarming islands " on gelatine; 20 hours' growth
at 20° C. x 3,000.
Fig. 2.—B. enteritidis sporogenes (Klein); microscopic double-stained preparation from a serum culture,
showing spores. X 2,000.
Fig. 3.—B. mesentericus sewage variety E; microscopic preparation from a 20 hours' agar culture at 20° C.
X 1,000.
Fig. 4.— B. mesentericus sewage variety E; microscopic preparation stained by V. Ermengem's method
and showing numerous flagella, from a 20 hours' agar culture at 20° C. x 1,000.
Fig. 5.—B. mesentericus sewage variety I; microscopic preparation from a 20 hours' agar culture at 20° C.
x 1,000.
Fig. 6.—B. mesentericus sewage variety I; microscopic preparation stained by V. Ermengem's method,
showing numerous flagella; from a 20 hours' agar culture at 20° C. x 1,000.
Fig. 7.—B. mesentericus sewage variety I; gelatine plate culture. About natural size.
Fig. 8.—B. mesentericus sewage variety I; gelatine "stab" cultures. From left to right—three days',
two days', one day's growth at 20° C. About natural size.
Fig. 9.—B. mesentericus sewage variety I; potato culture, one day's growth at 37° C. Very slightly
enlarged.
Fig. 10.—"Sewage proteus." Microscopic preparation from an agar culture; 24 hours' growth at 20° C.
X 1,000.
Fig. 11.—"Sewage proteus." Microscopic preparation stained by V. Ermengem's method, showing a single
flagellum at one end of each rod; from a 24 hours' growth agar culture at 20° C. X 1,000.
* Fig. 24, plate VI. † Fig. G, plate VIII.