GENUS BACTERIUM 293 



tributed throughout the medium both of which sink upon 

 agitation of the liquid. After 10 to 15 days a characteristic 

 brown color makes its appearance, diffused throughout the 

 medium, and the sediments become a deep brownish color. 

 This deepens to a deep brown with age. In glucose bouillon 

 the acidity is increased after some days and the characteristic 

 brown color does not appear, probably due to the acid. Gas 

 is not formed. Little or no change is produced in lactose or 

 saccharose bouillon. 



Life conditions and properties. This organism grows 

 best at about 20 C. ; 31 C. inhibits its growth. It is an 

 obligate aerobe. It does not produce indol. It reduces 

 nitrates to nitrites and finally to ammonia. 



Resistance. It is destroyed by an exposure of 10 min- 

 utes in bouillon cultures to a temperature between 42 and 

 43 C. 



Pathogenesis. This organism is fatal to brook trout in 

 a few days when injected either beneath the skin or in the 

 peritoneal cavity. The fatal results occur after a longer time 

 when the cultures are mixed with the food. It was not fatal 

 to frogs. 



BACTERIUM DIPHTHEEIAE (LOEFFLER) MIGULA. 



Synonyms. Cory neb act erium diphtheriae Lehmann and 

 .Neumann ; Klebs - Loeffler bacillus. 



Place in nature. This bacterium is the cause of the 

 specific disease in man known as diphtheria. It has been re- 

 ported as the cause of a diphtheritic condition in cats and in 

 the horse. Gerhardt x reports the spread of diphtheria from 

 fowls suffering from the disease to workmen attending them. 

 There are numerous instances of this kind but the evidence is 

 not conclusive that the organism was the same. Holmes 2 

 reports diphtheria occurring in children in connection with 

 an outbreak of disease in cattle and fowls. It is quite gen- 



1 Gerhardt. Rem. f. Thierheilkunde in Viehzucht, Bd. VI (1883) 

 p. 180. 



2 Holmes. Jour. Comp. Path, and Therap., Vol. XVII (1904) p. 1. 



