GENUS BACTERIUM 285 



course of 36 hours. Then the bouillon gradually becomes clear, 

 while a granular sediment collects in the bottom of the tube. 

 A scaly, grayish white, greasy looking pellicle forms on the 

 surface and adheres closely to. the sides of the tube, but on 

 agitation it is broken into flaky masses which settle to the bot- 

 tom. A new pellicle is slowly formed, but it never becomes so 

 strong as the original one. It will grow in both alkaline and 

 acid broth (2% to phenolphthalein) but an acidity of 2.8% 

 kills the organism. Old bouillon cultures give a pronounced 

 alkaline reaction. Bouillon containing 1% dextrose in fermen- 

 tation tubes becomes cloudy in 36 hours, and after 48 hours a 

 pellicle is formed on the surface of the broth in the open bulb, 

 while a sediment appears at the elbow. Fermentation occurs 

 in the bulb, causing an acid reaction,. while the contents in the 

 closed tube remain unchanged (phenolphthalein test). Cul- 

 tures in lactose are not so vigorous as in dextrose, and in sac- 

 charose they are still less abundant. The bacteria have no 

 action upon the molecule of lactose or saccharose. Gas is not 

 produced during growth in any of these sugar-containing 

 media. 



Milk. In milk growth takes place without visible change. 



Life conditions and properties. The most favorable 

 temperature is about 37 C. Growth takes place slowly at 

 room temperature. No growth occurs at 43 C. It is an 

 aerobe and facultative anaerobe. It does not produce indol 

 and no specific toxin has been detected. 



Resistance. A temperature of 65 C. for 10 minutes 

 proves fatal. Drying and sunlight kill it in 6 days' exposure. 

 A 2.5% solution of carbolic acid destroyed life in one minute. 

 A 1-2000 solution of mercuric chloride proved fatal in four 

 minutes. Lime water was not effective after several hours. A 

 0.25% solution of formalin destroyed its vitality in six 

 minutes. 



Pathogenesis. This organism is fatal to guinea pigs, 

 when inoculated intravenously or intraabdominally, in from 

 four to ten days. The lesions are those of general infection 

 with foci in the kidneys and liver. When inoculated subcu- 



