iv MICROBES SIMULATING THE B. PESTIS 61 



viscid grey exudation. Both the peritoneal and the 

 pleural exudations contained in a gelatinous matrix 

 crowds of beautifully bipolar-stained oval bacilli. 



The result of the injection, the nature of the peritoneal 

 exudation, and the aspect and staining of the bacilli in 

 this exudation, were such that a mistake for B. pestis 

 could easily have been made. 



One further experiment only need be here detailed. 

 Of the viscid peritoneal exudation of guinea-pig 4 a few 

 drops were injected into the groin of two rats (Nos. 5 

 and 6) on April 12. On April 14 both animals seemed 

 affected ; they were quiet, their coats rough, their breath- 

 ing accelerated, and they did not feed normally. 



On April 15 the animals seemed a little better, though 

 not quite well. On April 1 6 one of the two rats appeared 

 much worse, and on April 17 it was found dead. Post 

 mortem there was in the groin a large tumour which 

 involved the subcutaneons tissue and the inguinal lymph 

 glands, which were infiltrated with sanguineous fluid. In 

 this fluid were crowds of bacilli, which in size and bipolar 

 staining resembled B. pestis. The peritoneum contained 

 slimy grey pseudomembranes covering the surface of the 

 liver, the spleen, and the parietes. These pseudomem- 

 branes consisted of an interstitial gelatinous matrix, em- 

 bedded in which were bacilli of the size of B. pestis, 

 showing (in stained films) exquisite bipolar staining. In 

 the omentum were hemorrhagic spots. The small intes- 

 tines were found much congested, relaxed, and contain- 

 ing sanguineous mucus. Both lungs were much inflamed. 



From this post-mortem examination, therefore, a 

 diagnosis of " plague " might have been justified. But 

 cultures of the peritoneal exudation, of the tissue and 



