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STUDY AND IDENTIFICATION OF BACTERIA. 



(Pasteurelloses), from which man suffers. It is primarily a disease of 

 rats. Other Pasteurelloses are chicken cholera and swine plague. 

 Where the plague bacilli are found chiefly in the glands, we have 

 bubonic plague; when in the lungs, pneumonic plague, and when as a 

 septicaemia, septicaemic plague. An intestinal type is recognized by 

 c-ome authors. It must be remembered that in all forms of plague the 

 lymphatic glands show hemorrhagic oedema; it is in bubonic plague, 

 however, that the areas of necrosis with periglandular oedema are 

 prominent. Where the symptoms are slight, mainly buboes, the term 

 pestis minor is sometimes used; the typical disease being termed 

 pestis major. In pneumonic plague we have a bronchopneumonia. 



FIG. 30. Colonies of plague bacilli forty-eight hours old. 

 (Kolle and Wassermann.} 



In smears from material from buboes, from sputum or in blood 

 smears, as well as from blood or spleen smears from experimental 

 animals, we obtain the typical morphology of a coccobacillus 1.5 

 x .$fj. with very characteristic bipolar staining; there being an interme- 

 diate, unstained area. Inoculating tubes of plain agar and 3% salt agar 

 with this same material, w r e obtain in plain agar cultures organisms which 

 are typically small, fairly slender rods, which do not stain characteris- 

 tically at each end and are not oval. The smear obtained from the 

 salt agar presents most remarkable involution forms coccoid; root- 

 shaped, sausage shaped forms, ranging from three to twelve microns 



