CHICKEN CHOLERA. 203 



the colonies are granular and concentric. It does not liquefy 

 gelatin. In stab-cultures its growth on this media resembles 

 that of a nail with a flat head, the head of the nail being 

 closer to the surface of the medium than the point. 



Its growth in agar and bouillon offers nothing character- 

 istic. The bacillus is strictly aerobic. 



Pathogenesis. Chickens, geese, pigeons, sparrows, mice, 

 and rabbits are susceptible animals. Guinea-pigs are im- 

 mune. By inoculation the disease produced in susceptible 

 animals is that of a general septicaemia, the bacillus being 

 found in the blood and all the internal organs. 



By feeding the contaminated material to animals the lesions 

 are limited to the intestines, having the appearance of true 

 cholera. 



Protective inoculations have been performed by using atten- 

 uated cultures, the attenuation being arrived at, as recom- 

 mended by Pasteur, by using cultures two or three months 

 old. This bacillus has been used extensively in Australia 

 for the destruction of rabbits. It is said that Avith two 

 gallons of a bouillon culture as many as 2000 rabbits may be 

 destroyed. 



This bacillus has been described by different authors under 

 a number of names : as the bacillus of rabbit septicaemia, by 

 Koch ; the bacillus of swine plague, by Loeffler ; Bacilli cuni- 

 cucilidi, by Fluegge, and others. 



MORAX-AXENFELD BACILLUS. 



History. In some cases of subacute conjunctivitis Morax, 

 in' 1896, found a diplobacillus which he described as the etio- 

 logical factor. Axenfeld, shortly after, corroborated his 

 findings. 



Morphology and Staining. This bacillus is about 2 //. long, 

 ovoid in shape, and generally placed end to end in pairs. It 

 is stained readily by the usual aniline dyes and not by Gram's 

 method. 



Biologic Characters. It grows on all media containing 

 blood-serum and of alkaline reaction. Loeffler's blood-serum 

 mixture is liquefied. 



