PATHOGENIC PROPERTIES OF CAUSATIVE AGENTS. 125 



Diplobacillus pneumonias Friedlander readily destroys 

 mice and guinea-pigs on subcutaneous and intravenous in- 

 jection, and dogs and rabbits less readily. Postmortem 

 examination discloses here, also, septicemia. 



Bacillus pyocyaneus, when employed in considerable 

 amounts, is pathogenic for guinea-pigs and rabbits, inducing 

 local suppuration, diarrhea, and sepsis. 



Bacterium coli commune : Mice, guinea-pigs, rabbits, 

 and dogs are susceptible to subcutaneous, intraperitoneal 

 or intravenous injection. There result local abscesses, 

 hemorrhagic diarrhea, and septic manifestations ; post- 

 mortem examination disclosing marked hyperemia of all 

 the abdominal organs, and often septicemia. 



In conclusion, it may be again especially emphasized that 

 the results obtained in experiments on animals with all of 

 these common causative agents of inflammation are by no 

 means constant. They vary quite extraordinarily, in ac- 

 cordance with the virulence of the material employed, and 

 the inoculations frequently enough pursue a completely 

 negative course. The virulence of the exciting agents of 

 inflammation varies, however, according to their source. 

 The bacteria, for instance, cultivated from a fatal pyemia, 

 are much more virulent than the relatively harmless bacte- 

 ria derived from a mild suppuration of the skin, etc. It is 

 to be emphasized, further, that all of these exciting agents 

 of suppuration and inflammation are not exclusively 

 pyogenic, but they may also induce purely serous pro- 

 cesses : as, in the main, the three principal varieties of in- 

 flammation the serous, the fibrinous, and the purulent 

 differ from one another only quantitatively. 



THE OCCURRENCE OF THE CAUSATIVE AGENTS OF 



INFLAMMATION AND SUPPURATION IN HEALTHY 



PERSONS AND OUTSIDE THE BODY. 



Staphylococci have been found in dust, upon the sur- 

 face of the earth, in the air, in household wash-water ; 

 further, almost constantly upon the surface of the skin, in 

 the accumulations beneath the finger-nails, in the saliva, 

 in the mucus of the pharynx, in the nasal secretion, in 

 the intestinal contents, in the vagina, and in the urethra. 



Streptococci have been cultivated from the air of hospi- 



