Pathogenic Bacteria

398

PATHOGENIC BACTERIA.

Characteristics for
TYPHOID BACILLUS.

Bacilli usually slender.

Flagella numerous (10-20), long, and
wavy.

Growth not very rapid, not particularly
luxuriant.

Upon Eisner's culture-medium de-
velops slowly, the colonies remain-
ing small.

Upon fresh acid potato the so-called
" invisible growth " formerly thought
to be differential.

Acid-production in whey not exceed-
ing 3 per cent. Sometimes slight
in ordinary media, and sometimes
succeeded by alkaline production.

Grows in media" containing sugars
without producing any gases.

Produces no indol.

Growth in milk unaccompanied by
coagulation.

In Maassen's asparagin-glycerin solu-
tion the bacillus does not grow.

Gives the Widal reaction with the
serum of typhoid blood.

Differentiation.

COLON BACILLUS.
Bacilli inclined to be a little thicker.
Flagella fewer (8-1 o).

Growth rapid and luxuriant. This
character is by no means constant.

Upon Eisner's medium develops more
rapidly, the colonies being larger.
(Sometimes the colonies are small
and remain so.)

Upon potato a brownish-yellow, dis-
tinct pellicle.

Acid-production well marked.

Gas-production well marked.

Indol-production marked.
Milk coagulated.

Grows in Maassen's solution.
Does not react with typhoid blood.