464 BACTERIOLOGY. 



between 56 and 60 0., the time of exposure being 

 ten minutes (Sternberg). Bolton found that a 1 per 

 cent, solution of carbolic acid destroyed the vitality 

 after two hours' exposure. Mercuric chloride, 1 : 1000, 

 destroys it in from five to ten minutes, according to 

 most authorities, though Abbott found that in the 

 same culture there may be a considerable difference in 

 the resisting power of the cocci, all being frequently 

 destroyed in five minutes, while, again, some may sur- 

 vive after an exposure to a solution of 1 : 1000 for ten, 

 twenty, and even thirty minutes. 



Pathogenesis. The pathogenic effect of the staphylo- 

 coccus pyogenes aureus on test animals varies consider- 

 ably according to the mode of application and the 

 virulence of the special culture employed. In the exper- 

 iments so far made this micrococcus, as found in sup- 

 purative processes in the human subject, has not proved 

 to be as infectious for animals as it is for man. In 

 man a simple rubbing of the surface of the unbroken skin 

 with pus from an acute abscess is, as a rule, sufficient 

 to produce purulent inflammation, and the introduction 

 of a few germs from a septic case into a wound may lead 

 to a fatal pysemia. These conditions can only be repro- 

 duced in lower animajs with difficulty and by the inocu- 

 lation of large quantities of the culture. Subcutaneous 

 injections, or the inoculation of open wounds in mice, 

 guinea-pigs, and rabbits, are commonly without result; 

 occasionally abscess formation may follow at the point 

 of inoculation, which usually ends in recovery. The 

 pus-producing property of the organism is exhibited 

 in proportion to the virulence of the culture employed. 

 Slightly virulent cultures, which constitute the majority 

 of those obtained from pus taken from the human sub- 



