THE AVIAN PASTEURELLA 447 



varieties of the same bacillus, and the conclusion arrived at is in short this : 

 that there is one Pasteurella, which can pass from one animal species to 

 another, and which by adaptation in one species can produce a disease peculiar 

 to that species. 



Chamberland and Jouan showed that the avian pasteurella could naturally infect 

 pigs and the swine pasteurella fowls. 



By passage through rabbits in the laboratory the ovine pasteurella acquires the 

 properties of the avian, and similarly, by passage through guinea-pigs, young 

 chickens and fowls the swine pasteurella acquires the characteristics of the avian 

 pasteurella. 



Immunization with one variety establishes immunity against that as well as 

 against the other varieties : thus, rabbits vaccinated with the swine pasteurella are 

 at the same time immunized against the fowl pasteurella, and so on. 



A description of the disease (Pasteur ellosis] as it occurs in different animals 

 will now be given, but it must be distinctly understood that this plan of 

 dealing with the subject is adopted merely for convenience, and does not 

 imply any doubt as to the truth of Nocard's view of the specific identity of 

 the organisms found in the different species of animals. 



Characteristics common to the pasteurella group. Organisms of the pas- 

 teurella group are non-motile cocco-bacilli, gram-negative, very pleomorphic 

 and staining more deeply at the ends than in the centre [cf. B. pestis]. They 

 do not form spores, do not liquefy gelatin nor coagulate milk, they give no 

 visible growth on potato, are primarily aerobic but can be grown anaerobically. 

 They give rise in culture to a peculiar and characteristic odour. 



According to Lignieres these organisms do not produce indol in culture, but old 

 cultures of the bacillus of fowl cholera (the avian pasteurella) certainly contain 

 indol. 



[The pasteurelloses and plague in animals. Attention must be drawn to 

 the close resemblance which exists between the bacilli of the pasteurella group 

 on the one hand and the plague bacillus on the other, and also to the similarity 

 of the lesions naturally produced by these organisms. Not only are these 

 bacilli very much alike, indeed almost identical, in their morphological 

 appearances and cultural characteristics, but the naked eye lesions produced 

 in naturally infected animals are also very similar. Mistakes are therefore 

 certain to be made unless in every case the causal organism is isolated and 

 differential tests applied. 



[Culturally the plague bacillus is most readily differentiated from bacilli 

 of the pasteurella group by an observation of the growth in MacConkey's 

 sodium taurocholate medium (p. 412) containing the following carbohydrates 

 glucose, Isevulose, mannite and galactose. The plague bacillus grows in all 

 these media, producing acid but no gas. The bacilli of the pasteurella group 

 do not grow in MacConkey's medium (Indian Plague Commission). 



[The formation of stalactites in broth culture is not a feature peculiar to 

 the plague bacillus but is possessed also by, at any rate, many of the 

 pasteurella bacilli. 



[Animal inoculation will further assist the differential diagnosis (cf. Plague). ] 



1. PASTEURELLA GALLING. 



(The bacillus of fowl cholera.) 



Pasteur was the first to describe the avian pasteurella, though it had 

 previously been seen by Moritz, Perron9ito, and by Toussaint. 



Fowl cholera (fowl plague, fowl septicaemia, fowl typhoid) is an epizootic 

 disease of the Gallinaceae (fowls, pheasants, guinea-fowl, turkeys and pigeons) 



