196 OEIENTAL PLAGUE chap. 



relaxed, and filled with blood and mucus ; at one point of 

 the congested ileum a Peyer's gland appeared swollen, 

 much projecting, and necrotic, the membrane forming 

 around it a well-marked ring of haemorrhage ; the mes- 

 enteric glands were enlarged and hemorrhagic (Fig. 86) ; 

 the spleen large, dark, and firm ; the lungs of both sides 

 were much congested and showed haemorrhages. The 

 sanguineous mucus of the ileum, the mesenteric glands, 

 the spleen, and the lungs were crowded with B. pestis (as 

 was proved by film specimens and cultures) ; the blood 

 also contained abundance of B. pestis. 



In this case, therefore, there was distinct and direct 

 evidence that plague had been contracted by the feeding ; 

 for here, as in former positive cases, the point of infection 

 was anatomically easily located in the ileum at a Peyer's 

 gland. Sections made through these parts fully confirmed 

 this inference. 



A small particle of the sanguineous mucus from the 

 ileum of the dead sewer rat was injected subcutaneously 

 into a guinea-pig, and the rest of the mucus was mixed 

 with bran and oats, dried over sulphuric acid, and then 

 given as food to two wild rats. As a result, the two rats 

 thus fed remained unaffected, whereas the inoculated 

 guinea-pig sickened and became affected with typical sub- 

 acute plague, the subcutaneous injection causing a huge 

 hemorrhagic and necrotic bubo in which was abundance 

 of B. pestis. 



It is of interest to notice in regard of this experiment 

 22, that a plague rat had been in the same cage with 

 another rat which remained unaffected, though fed with 

 plague material like its fellow — as indeed had happened 

 in previous experiments, Series I. and II. In these condi- 



