Pathogenic Bacteria

TETANUS.

275

in manure, and sometimes in the intestinal discharges
of animals. It is extremely difficult to isolate and culti-
vate, because it will not grow where the smallest amount
of oxygen is present.

The method now generally employed for the isolation
of this bacillus is that originated by Kitasato, and based
upon his observation that its spores can resist high temper-

FIG. 73.—Bacillus tetani: six-days- FIG. 74-—Bacillus tetani: culture
old puncture-culture in glucose-gelatin four days old in glucose-gelatin (Fran-
(Frankel and Pfeiffer). kel and Pfeiffer).

atures. After finding that the typical bacilli are present
in earth or pus, or whatever the material to be investi-
gated was, Kitasato exposed a'portion of it for an hour
to a temperature of 80° C. By .this heating all the fully-
developed bacteria, tetanus as well as the others, and the