Skip to main content

Full text of "Pathogenic Bacteria"

See other formats

PNEUMONIA.                           353

prefers to call it, the Bacillus pneumonias—has ceased to
be regarded as specific, and is now looked upon as an
accidental organism whose presence in the lung is, in
most cases, unimportant.

As the two organisms are similar in more respects than
their names, Friedlander's bacillus requires at least a
brief description.

It is distinctly a bacillus, but sometimes, when occur-
ring in pairs, has a close resemblance to the pneumo-
coccus of Frankel and Weichselbaum. Very frequently
it forms chains of four or more elements. It is also com-
monly surrounded by a transparent capsule. It is non-
motile, has no spores and no flagella. It stains well
with the ordinary anilin dyes, but does not retain the
color when stained by Grain's method.

Frankel points out that Friedlander's error in suppos-
ing this bacillus to be the chief parasite in pneumonia
depended upon the fact that his studies were made by
the plate method. If some of the pneumonic exudate be
mixed with gelatin and poured upon plates, the bacilli
grow into colonies at the end of twenty-four hours, and
appear as small white spheres which spread upon the
gelatin to form white masses of a considerable size.
Under the microscope these colonies are rather irregular
in outline and somewhat granular.

The bacillus grows at as low a temperature as 16° C.,
and, according to Sternberg, has a thermal death-point
of 56° C.

When a colony is transferred to a gelatin puncture-cul-
ture, quite a massive growth occurs. Upon the surface a.
somewhat elevated, rounded white mass is formed, and
in the track of the wire innumerable little colonies,
spring up and become confluent, so that a "nail-growth "
results. No liquefaction occurs. When old the cultures
sometimes become brown in color.

Upon the surface of agar-agar at ordinary temperatures
quite a luxuriant white or brownish-yellow, smeary, cir-