454 THE PASTEURELLA GROUP 



fluid, the lungs are congested and seem to float in a blood-stained effusion, 

 and the pericardium is full of fluid which is also occasionally blood-stained. 



2. [Post-mortem appearances in naturally infected rabbits and in spontaneous 

 plague in rabbits, (a) Rabbit septicaemia. In a case observed by C. J. Martin and 

 Rowland the right superficial inguinal gland was red and swollen, and the vessels 

 in the neighbourhood congested. The skin generally was injected, and both skin 

 and peritoneal lining had a pink flush. The spleen was enlarged and tense, and the 

 liver mottled. The pleurae and pericardium were full of fibrinous exudation, the 

 heart being adherent to the parietal pericardium and the lungs to the pleurae. There 

 was double pneumonia. The organism was found in the pleural exudate, lungs, 

 spleen and enlarged glands. 



[(&) Plague. In another rabbit from the same neighbourhood these observers 

 found a plague-infected rabbit which showed the following lesions : a typical sub- 

 maxillary bubo, and marked injection of the vessels in the skin. The spleen was 

 much enlarged tense and of a purplish colour. The peritoneum and pleurae con- 

 tained blood-stained fluid. The left lung was congested but not consolidated. 

 The intestines were matted together by recent lymph. 



[In a second rabbit the only lesion was a greatly enlarged spleen full of nodules.] 



3. Morphology. Microscopically the organism is similar to that of fowl 

 cholera (q.v.) [and may be indistinguishable from Bacillus pestis]. Its 

 growth on gelatin is white, slightly viscous and rather more abundant than 

 that of the fowl cholera bacillus. 



3. PASTEURELLA 8UI8. 



(The bacillus of contagious pneumonia of pigs or swine plague). 

 Ger. Schweineseuche. Fr. Pasteurellose du pore. 



The contagious pneumonia of pigs, known in America as " Swine plague " 

 and in Germany as " Schweineseuche," and caused by an organism of the 

 pasteurella group, must be carefully distinguished from Hog Cholera 1 (Chap. 

 LXIV.) with which it was for a long time confused. 



Clinically the differential diagnosis is very difficult and sometimes impossible, 

 and further, as Karlinski has shown, an animal may suffer from the two diseases 

 at the same time. Bacteriologically, the micro-organisms are very different ; the 

 organism of swine plague belongs to the pasteurella group and is closely allied to 

 the bacillus of fowl cholera, while the Hog Cholera bacillus or Bacillus suipestifer 

 belongs to the Salmonella group (p. 431). It should be stated however that Hutyra, 

 as a result of his investigations, inclines to the belief that hog-cholera and swine 

 plague (Schweineseuche) are one and the same disease and due to an invisible 

 micro-organism. 



[It would seem also that the pasteurella infection of pigs may be mistaken 

 for an infection with Bacillus pestis (cf. p. 461).] 



Experimental inoculation. The virulence of the swine pasteurella is ex- 

 ceedingly variable but if low is easily increased by passage. Mice and rabbits 

 soon succumb after being inoculated sub-cutaneously with a virulent strain ; 

 guinea-pigs are less susceptible ; in pigeons the inoculation of O5 c.c. of a 

 virulent culture into the muscles proves fatal. Fowls are more resistant, 

 but the inoculation of a virus which has been increased in virulence by passage 

 through guinea-pigs and chickens produces a fatal result. Dogs, sheep and 

 bovine animals succumb to intra-venous inoculation. 



Pigs as a rule after being inoculated sub-cutaneously merely suffer from a 

 local osdema at the site of inoculation and a transitory rise of temperature ; 

 when inoculated however with a very virulent virus a fatal result may ensue. 



[* Hog cholera is also known as swine fever and swine typhoid and in Germany as 

 Schweinepest. ] 



