532 PATHOGENIC AEROBIC BACILLI 
be no growth, or it may be scanty and of a white color. In milk, at 
37° C., an acid reaction and coagulation of the casein are produced at 
the end of eight or ten days, In the absence of oxygen this bacillus 
is able to grow in solutions containing grape sugar (Escherich). In 
bouillon it grows rapidly, producing a milky opacity of the culture 
liquid. The thermal death-point of Emmerich’s bacillus, and of the 
colon bacillus from feces, was found by Weisser to be 60° C., the 
time of exposure being ten minutes. The writer has obtained corre- 
sponding results. Weisser found that when the bacilli from a bouil- 
lon culture were dried upon thin glass covers they failed to grow 
Fia. 145. Fig. 146. 
Fia. 145.—Bacillus coli communis in nutrient gelatin containing twenty per cent of gelatin, end 
of two weeks, showing moss-like tufts along the line of growth. (Sternberg.) 
Fie. 146.—A portion of the growth shown in Fig 147, at a, magnified about six diameters. 
From a photograph. (Sternberg.> 
after twenty-four hours. These results give confirmation to the 
view that the bacillus under consideration does not form spores. 
This view receives further support from the experiments of Wal- 
liczek (1894), who found that when dried upon pieces of sterile filter 
paper the bacillus failed to grow at the end of eighteen hours. 
Pathogenesis.—Comparatively small amounts of a pure culture 
of the colon bacillus injected into the circulation of a guinea-pig 
usually cause the death of the animal in from one to three days, and 
the bacillus is found in considerable numbers in its blood. But when 
