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, etc. 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 septicaemia or pyiiemia, tliey exist 



