138 OMENTAL PLAGUE chap. 



of guinea-pigs with plague materials or with culture of 

 B. pestis, and now we wish to give a general summary of 

 the observations concerning these rodents. 



As has been repeatedly mentioned, the guinea-pig 

 injected subcutaneously in the groin with a small dose 

 of virulent plague material or of virulent culture develops 

 rapidly (within twenty-four hours) a soft swelling, which 

 within forty -eight hours reaches a considerable size — 

 filbert to pigeon's egg ; the animal is now distinctly quiet, 

 sits in the corner of its cage with curved back — " is 

 lumpy," — and does not feed. It is found dead in or 

 before seventy-two hours. On post-mortem examination 

 the inguinal glands of the injected side are enlarged, 

 firm, and on incision show haemorrhages ; the subcutaneous 

 tissue around the gland is much cedematous and contains 

 many petechia and effused blood; this hemorrhagic 

 condition of the peri-lymphatic tissue, being sometimes 

 very extensive, may reach to the middle line of the 

 abdomen and even beyond, and may in some cases extend 

 upwards and over the chest. In the hemorrhagic 

 cedematous tissue the B. pestis largely abound, as is 

 shown by film specimens and by culture. The inguinal 

 lymph gland itself is packed with B. pestis, which on 

 staining are distinctly bipolar. On opening the abdomen 

 the large, dark, firm spleen and liver attract attention ; 

 film specimens of a cut surface of these organs and culture 

 yield enormous masses of B. pestis, bipolar in staining. 

 In some cases the intestines (small and also large) show 

 numerous punctiform haemorrhages in their serous coat ; 

 the small intestine is relaxed and contains sanguineous 

 mucus, the mesenteric glands in these instances being 

 swollen and showing haemorrhage. In these positive 



