448 BACTERIOLOGY. 
a bouillon culture were dried upon thin glass covers 
they failed to grow after twenty-four hours (Weisser). 
Waliczek found that when dried upon pieces of sterile 
filter-paper they failed to grow at the end of eighteen 
hours. These results give confirmation to the view 
that the colon bacillus does not form spores. 
Pathogenesis. The colon bacillus is pathogenic in 
varying degrees for test animals, though the results of 
the inoculations, as with the typhoid bacillus, cannot 
always be predicted with certainty. Intraperitoneal 
injections of from 0.1 to 1 ¢.c. of fresh, virulent cul- 
tures usually produce death in mice at the end of from 
one to eight days, but death does not invariably follow. 
The more rapidly death ensues the greater the number 
of bacilli found in the body; they are always more 
abundant in the abdominal cavity than in the blood; 
in other words, the result is to be attributed to the 
toxic rather than to the infective properties of the 
culture used. But the fact that the bacilli are found 
in the blood and internal organs when death rapidly 
follows inoculation proves that they do multiply to 
some extent in the body. When less virulent cultures, 
however, are injected and death results, this is due to 
the poisonous products formed by the bacilli and given 
up at their death. The lesions produced are those of 
enteritis: the duodenum and jejunum are found to con- 
tain fluid, the spleen is somewhat enlarged, and there 
is marked hyperemia and ecchymosis of ‘the small in- 
testines, together with swelling of Peyer’s patches. 
Intraperitoneal and intravenous inoculation of guinea- 
pigs and rabbits may also produce death, which, when 
it follows, usually takes place within the first forty-eight 
hours, accompanied by a decided fall of temperature, 
