PLAGUE 115 



bouillon, characteristics which were just the opposite of those of the 

 organism reported by Yersin. 



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

 when in lungs, pneumonic plague; when localized in the skin and subcutaneous tissue, 

 the cellulo-cutaneous; and when as a septicaemia, septicaemic plague. An intestinal 

 type is recognized by some authors. It must be remembered that in all forms of 

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

 ever, 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. 



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 



FIG. 3 1 .Colonies of plague bacilli forty-eight hours old. (Kolle and Wassermann.') 



morphology of a coccobacUlus (1.5X0.5*1) with very characteristic bipolar staining; 

 there being an intermediate, unstained area. Very characteristic also is the appear- 

 ance in these smears of degenerate types which stain feebly and show coccoid and 

 inflated oval forms. The presence of these involution forms associated with typical 

 bacilli is almost diagnostic for one with experience. Inoculating tubes of plain agar 

 and 3% salt agar with this same material, we obtain in plain agar cultures organisms 

 which are typically small, fairly slender rods, which do not stain characteristically 

 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 3 to 12 microns in length, more resembling cultures of moulds than 

 bacteria. Another point is that on the inoculated plain agar we are in doubt at 

 the end of twenty-four hours whether the dewdrop-like colonies are really bacterial 

 colonies or only condensation particles. By the second day, however, these colo 

 have an opaque grayish appearance, so that now, instead of questioning the presi 



