284 BACTERIOLOGY. 



ture as 18° C. From 42° C. oq the development is 

 checked. 



Under most favorable conditions the growth is very 

 slow. It grows as well without as with oxygen. It is, 

 therefore, one of the facultative anaerobic forma. 



The most successful efforts at the cultivation of this 

 organism ai-e those seen when the agar-agar-gelatin 

 mixture of Guarniari is employed. (See this medium.) 



It may be stained with the ordinary aniline staining- 

 reagents. For demonstrabing the capsule the method 

 of Gram and the acetic acid method give the best 

 results. (See Stainings.) 



This organism is conspicuous for the irregularity 

 of its behavior when grown under artificial conditions; 

 usually it loses its pathogenic properties after a few 

 generations; but again this peculiarity may be re- 

 tained for a much longer time. Not rarely it fails to 

 grow after three or four transplantations on artificial 

 media, though at times it may be carried through many 

 generations. 



Inoculation into animals. The results of inoculations 

 with pure cultures of this organism are also conspicuous 

 for their irregularity. When the organism is of full 

 virulence the form of septicsemia just described is 

 usually produced, but at times it is found to be totally 

 devoid of pathogenic powers; between these extremes 

 cultures may be obtained possessing all variations in 

 the intensity of- their disease-producing properties. 

 The principal pathological conditions that may be pro- 

 duced by this organism by inoculations into animals, 

 according to the degree of its virulence, are acute septi- 

 csemia, spreading inflammatory exudations, and cir- 

 cumscribed abscesses. All three of these conditions 



