BACILLUS COLI COMMUNIS. 167 



is not altogether stopped until 45 C. is reached. Exposure 

 to a temperature of 65 C. for five minutes destroys the bac- 

 teria. Exposure to cold has no effect on the bacteria, and in 

 some instances the author has been able to cultivate bacteria 

 which had been exposed to the temperature of liquefied air 

 for several minutes. 



In bouillon the bacillus grows very rapidly and renders the 

 bouillon cloudy ; pellicles are formed on the surface of the 

 medium, and there is also a thick deposit at the bottom of 

 the tube. A strong fecal odor can be detected. 



On gelatin plates the colonies appear as small, spherical, 

 blue-gray points, somewhat dentated at the margin. With a 

 magnifying glass the colonies are brownish, lozenge-shaped 

 or irregularly round, coarsely granular. In gelatin stab- 

 cultures along the track of the needle are seen a series of 

 small spherical colonies in rows and separated from each other. 

 On the surface of the tube the growth is of a dirty gray 

 color. It does not liquefy gelatin. 



On agar-agar the growth has nothing characteristic. On 

 agar to which 2 per cent, glucose has been added bubbles may 

 be seen along the line of growth, due to the gases of fermen- 

 tation. On lactose-litmus-agar the colonies develop very 

 rapidly and are of a pinkish color. On potato it grows rap- 

 idly in the beginning, being of a bright-yellow color which later 

 becomes browu. The growth in serum is similar to that on agar. 



It produces indol in peptone solution and coagulates milk 

 very rapidly. It ferments lactose- and glucose-bouillon. 



Pathogenesis. Bouillon cultures of this bacillus injected 

 intravenously or into the peritoneal cavity of a rabbit cause 

 death in less than twenty-four hours. On autopsy intense 

 hypersemia of the peritoneum, ecchymotic spots of the intes- 

 tines, swelling of Peyer's patches, and enlargement of the 

 spleen are found. Subcutaneous inoculations are followed by 

 abscesses formed at the point of inoculation and by internal 

 conditions similar to those produced by intravascular injec- 

 tions. Injected into the pleural cavity it gives rise in twenty- 

 four hours to a purulent pleurisy accompanied by a large 

 effusion in the cavity and the formation of false membrane. 



