166 OKIENTAL PLAGUE chap. 



the mesenteric glands, and the vascular system in general, 

 had become literally crowded with the B. pestis. This is 

 a result more intensive in respect of the distribution of the 

 B. pestis in the affected animal than that which occurred 

 after subcutaneous or cutaneous injection. 



Experiment 3. — Four rats, Nos. 4, 5, 6, and 7 (kept 

 in couples in cages), were fed on May 10 with bread 

 mixed with gelatine cultures of B. pestis. The cultures 

 were six weeks old and contained abundance of typical 

 colonies ; but the gelatine around them was almost dry, 

 and the colonies themselves were dry -looking and 

 shrivelled. 



Eat No. 4 was found dead on May 1 3 ; rats Nos. 

 5 and 6 on May 14. Kat No. 7 appeared quiet at this 

 date, but by May 17 had become quite normal, and it 

 remained so. 



The post-mortem examination of rat No. 4 showed the 

 following appearances : — Both mammary glands much 

 congested and showing streaky haemorrhages ; sections 

 through the hardened tissue showed a great deal of effused 

 blood in the alveolar tissue, with numerous B. pestis. 

 The omentum was congested, and there were numerous 

 petechias in the ileum ; a distinct patch of haemorrhage 

 was seen around a swollen Peyer's gland ; the mesenteric 

 glands were swollen and haemorrhagic ; the spleen was 

 typically enlarged, dark, and firm ; the other viscera were 

 congested. Cultures and film specimens of the mesenteric 

 glands, of the interior of the intestine at the seat of 

 haemorrhage, of the spleen, and of the heart's blood 

 showed copious presence of B. pestis. 



Kat No. 5. — The whole of the lower ileum was relaxed 

 and filled with a sanguineous mucus ; several Peyer's 



