12 OMENTAL PLAGUE chap. 



have failed to find them either in the numerous film 

 specimens or in the numerous sections which I have 

 examined of the above two Hull cases of pneumonic 

 plague ; all these showed everywhere only oval or 

 cylindrical bipolar bacilli. 



II. Plague in Animals 



The chief animal to be considered in this connec- 

 tion is, of course, the rat, and of this species I have had 

 the opportunity to examine in several instances rats 

 naturally dead of plague, while in other instances dead 

 rats were found to have been affected with another 

 microbe, not B. pestis (see below). 



I will describe here the appearances in rats that had 

 died of plague in docks and in warehouses in Cardiff. 



P.M. — The most strikingly affected organ was the 

 spleen, this organ being dark red, firm, and at least twice 

 its normal size ; when cut into, it showed a fairly dry cut 

 surface ; cover-glass impressions made of the cut surface, 

 stained and mounted, showed everywhere abundance of 

 cylindrical bacilli with rounded ends and marked bipolar 

 staining ; the liver, kidneys, and lungs were more or less 

 congested, so were almost all lymph glands — film specimens 

 of all these organs showing abundance of typical cylindri- 

 cal bipolar B. pestis. The heart's blood contained 

 likewise abundance of B. pestis. The small intestine — 

 particularly the ileum — was relaxed and contained san- 

 guineous mucus, in which numerous bipolar plague-like 

 bacilli could be recognised. The bladder was in one case 

 distended, and filled with blood -tinged urine ; in others 

 it was collapsed and empty. In the blood-tinged urine, 



