vi PLAGUE INDUCED IN OTHER KODENTS 139 



instances, that is positive as regards the intestines, the 

 sanguineous mucus and the juice of the mesenteric glands 

 always yield B. pestis, and injection of animals with the 

 intestinal mucus yields positive result — acute plague. 

 But in other instances the intestines show nothing marked 

 beyond general injection. In some instances the urine of 

 the bladder is tinged with blood, and then the urine 

 injected into rodents causes plague. 



The liver, the suprarenals, the kidneys, and the lungs 

 show congestion. The heart's blood and the blood of all 

 viscera contain B. pestis, and, as culture proves, in 

 considerable numbers, although film specimens may, 

 owing to the scattered distribution of the comparatively 

 few B. pestis, not suggest it. 



If the infecting material is, however, of subnormal 

 virulence, the subcutaneous injection does not cause the 

 above acute form of plague, but leads to the subacute 

 form, death occurring after four or five days or later. 

 On post-mortem examination it is found that the bubo 

 shows necrotic foci in the lymph gland, the spleen is more 

 or less enlarged, granular, and mottled with numerous 

 necrotic nodules. The liver in the early fatal cases may 

 contain only very few punctiform grey dots of necrotic 

 change ; in late fatal cases it is generally crowded with 

 them. The lungs in early fatal cases show punctiform or 

 patchy hsemorrhages ; in the late fatal cases one or both 

 lungs show necrotic consolidations, some punctiform, 

 others patchy and extensive, involving occasionally a 

 whole lobe. Film specimens of these patches show con- 

 tinuous and dense masses of B. pestis, with well-marked 

 bipolar arrangement on staining. 



Inoculated cutaneously — care being taken that the 



