464 BACTERIOLOGY. 
between 56° and 60° C., 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 aseptic case into a wound may lead 
toa fatal pyeemia. These conditions can only be repro- 
duced in lower animals 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- 
