122 ORIENTAL PLAGUE chap. 



rubbed into several crossed incisions. In the case of rat 

 1r a large dose of culture was injected subcutaneously into 

 the groin. 



The subsequent history of these animals is as follows : — 



Eat lo died between fifth and sixth days. 



Rat 1p, which appeared normal, was killed on the 

 eighteenth day ; completely negative result. 



Rat 1q, which died on the fourth day, showed post 

 mortem : swollen lymph glands, with haemorrhage, in both 

 inguinal regions ; spleen large ; lungs congested. Spleen, 

 bubo, and heart's blood yielded crowds of colonies of 

 B. pestis of the type 2. 



Rat 1r died on the seventh day. As mentioned above, 

 this rat had been injected subcutaneously. The post- 

 mortem examination showed : bubo in groin at injected 

 side ; spleen slightly enlarged ; intestines congested. 

 Cultures of the spleen brought forth a fair number 

 of colonies of B. pestis (type 2) ; cultures of heart's 

 blood yielded a small number of colonies of the same 

 type (2). 



In all these instances there are seen, therefore, the same 

 features not only as regards virulence and pathological 

 result, but also as regards the preservation of type 2. 



Experiment 15. — This same type 2 of B. pestis 

 (derived from rat 1l) was used for cutaneous inoculation 

 of mice, and at the same time other mice were cutaneously 

 inoculated with B. pestis of type 1 (Cardiff bubo), with 

 result as follows : — 



Two mice (1 and 2) were inoculated cutaneously at 

 the root of the tail . with a forty-eight hours agar sub- 

 culture from spleen of rat 1l. 



Two mice (3 and 4) were cutaneously inoculated with 



