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.