vi PLAGUE INDUCED IN OTHEK EODENTS 145 



thigh with a few minims of emulsion of recent agar 

 culture of virulent B. pestis, the disease does not declare 

 itself before two or three days, by which time the animal 

 appears quiet and refuses food. The next day the animal 

 is manifestly ill, is drowsy, and sits with curved back in 

 a corner of its cage. It is found dead the next morning. 



On post-mortem examination the following appearances 

 are found : — The inguinal lymph glands are swollen and 

 inflamed, the surrounding tissue is ©edematous. The juice 

 of the lymph gland contains crowds of B. pestis. The 

 spleen is enlarged ; film specimens show abundance of 

 B. pestis. The most strikingly affected organ is the 

 liver, it being considerably enlarged and its vessels 

 engorged with blood. An impression of the cut end 

 of an incision into the liver substance shows all the 

 blood-vessels engorged with blood, comparatively few 

 bacilli in the vessels, but the spaces in which the 

 cylinders of liver cells are contained — the lymph spaces 

 — contain great abundance of B. pestis. The lungs 

 show great congestion ; the blood contains numerous 

 B. pestis, but less so than the liver substance. Stained 

 film specimens of all the above organs show the B. pestis 

 markedly cylindrical and bipolarly stained. Cultures of 

 the juice of the inflamed lymph glands, of the spleen, 

 liver, and heart's blood yield pure growth of B. pestis. 



Inoculation of rats and guinea-pigs with the juice of 

 the swollen lymph glands proves that the B. pestis is 

 highly virulent for these rodents. 



