114 STUDY AND IDENTIFICATION OF BACTERIA 



GRAM NEGATIVE BACILLI GROWING ON ORDINARY MEDIA 



Bacillus Pneumonias (Friedlander, 1882). This organism is re- 

 sponsible for about 5% of the cases of pneumonia. It is usually 

 termed the Pneumobacillus to distinguish it from the Pneumococcus; 

 at other times Friedlander's bacillus. The name of Fraenkel attaches 

 to the Pneumococcus. Morphologically, it is a short, thick bacillus, 

 and in pathological material, as sputum, shows a wide capsule. It is 

 nonmotile and Gram-negative. The colonies on agar are of a pearly 

 whiteness and are markedly viscid. On potato it shows a thick viscid 

 growth containing gas bubbles. The characteristic culture is the nail 

 culture of a gelatin stab. The growth at the surface is heaped up like a 

 round-headed nail, the line of puncture resembling the shaft of the nail. 



It does not liquefy gelatin. It does not produce indol, and does not produce gas 

 in lactose bouillon differences from the colon bacillus with which it may be con- 

 fused in cultures, as it does not then possess a capsule. If in doubt, inject a mouse 

 at the root of the tail. Death from septicaemia occurs in two days. The peritoneum 

 is sticky and numerous capsulated bacilli are present in the blood and organs. The 

 organisms which have been isolated from rhinoscleroma and ozcena are practically 

 identical with the B. pneumonia. This group of organisms is generally referred 

 to as the Friedlander group. Similar organisms have been isolated from the dis- 

 charges of middle-ear diseases and in anginas. Cases have been reported where the 

 B. pneumonia was the cause of septicaemia in man. 



Bacillus Pestis (Kitasato, Yersin, 1894). This is the organism of 

 plague. It is primarily a disease of rats. It is the member of the group 

 of haemorrhagic septicaemias (Pasteurelloses), from which man suffers. 



Other Pasteurelloses are chicken cholera, swine plague, mouse sep- 

 ticaemia and rabbit septicaemia. This is a widely distributed group and 

 may include saprophytic organisms as well as those noted for their 

 virulence. 



B. cholera gallinarum and B. suisepticus are approximately similar in 

 size and cultural requirements to B. pestis. The oval bacillus with 

 bipolar staining in smears from tissues is very characteristic for both 

 of them. Another name for swine plague (B. suisepticus) is infectious 

 pneumonia of swine. The organism is chiefly found in the lungs. The 

 bacillus of plague was first isolated by Yersin from a plague bubo, in 

 1894, at Hong Kong. It is true that Kitasato reported a bacillus 

 which he had isolated from the blood of a plague patient, on July 7, 

 1894 (Yersin's report was made July 30, 1894). Kitasato's bacillus 

 was motile, Gram-positive, coagulated milk and gave a turbidity in 



