92 BACTERIOLOGY. 
bacillus. The development of the streptococcus or 
pneumococcus in the endocardium or pleural cavity is 
followed by a serous exudation, frequently with more or 
less fibrin production. The formation of pus results, 
more especially from the streptococcus, pneumococcus, 
and staphylococcus; but also nearly all forms of bacteria, 
when they accumulate in one locality, may produce 
purulent inflammation. The colon, typhoid, and influ- 
_enza bacilli frequently cause the formation of abscesses. 
Catarrhal inflammation, with or without pus, follows 
the absorption of the products of many bacteria, such as 
the gonococcus, pneumococcus, streptococcus, and in- 
fluenza bacillus, ete. The hemorrhagic exudation seen 
in pneumonia is due to the pneumococcus; it is observed 
also in anthrax and other infections. Cell necrosis is 
produced frequently by the products of the diphtheria 
and of the typhoid bacilli and by those of other bac- 
teria. Specific proliferative inflammation follows the 
localization of the products derived from the tubercle 
bacillus and the leprosy bacillus. 
Not only can one species of bacteria produce several 
forms of inflammation, but the same organism will vary 
as to the kind or kinds of inflammation it will produce; 
this depending, first, upon its own characteristics at the 
time as to virulence, etc., and, second, upon the con- 
ditions in the infected animal, such as its health and 
power of resistance, the period of infection, and the 
circumstances under which the animal remains. Such 
variations, therefore, are in no case specific, for different 
poisons will produce changes which appear identical. 
The Manner in which Bacteria Produce Disease. The 
actual mechanical presence of the bacteria is only of 
importance when, as in septicemia or pyzemia, they exist 
