200	PA THOGENIC BA CTERIA,
are easily prepared,  as the thermal death-point deter-
mined by Sternberg is 56° C.
The bacillus appears to be rather common as a sapro-
phyte, and, as it has been found in the perspiration,
probably is not uncommon upon the skin.
Before leaving the subject of suppuration attention
must be called to several rather common bacteria which
may at times be the cause of troublesome suppuration.
Among these are the pneumococcus of Frankel and
Weichselbaum, the typhoid bacillus, and the Bacillus
coli communis (q. z>.).
The pneumococcus has not infrequently been discov-
ered most unexpectedly in abscesses of the brain and
other deep-seated organs, and seems to have powerful
chemotactic powers. For a careful consideration of it
the reader must be referred to the chapter upon Pneumo-
nia, where it is considered in full.
The Bacillus coli communis, which is always present in
the intestine, seems at times to enter the blood- or lymph-
channels and stimulate suppuration, and numerous cases
are on record showing this. The points most frequently
attacked seem to be the bile-ducts and the vermiform ap-
pendix, though the significance of the organism in appen-
dicitis has no doubt been overrated. It has also been found
in the kidney in scarlatinal nephritis, and is thought to
be the exciting cause of some cases. It was originally
described by Passet as the Bacillus pyogenes foetidus.
For a more particular study of this organism the reader
is referred to the chapter devoted to its consideration.
The Bacillus typhosus is probably less frequently a cause
of suppuration than either of the others, yet it seems to
be the occasional cause of the purulent sequelae of typhoid
fever. A case has recently been reported by Flexner in
which metastatic abscesses were found to be caused by it.
The Micrococcus tetragenus has also been found in the
pus of acute abscesses: it is quite common in the cavities
of pulmonary tuberculosis, and may aid in the destructive
processes involved in the general phthisical infection.