v PLAGUE IN THE EAT 125 



the above necrotic nodules in spleen, liver, and often 

 lung. 



Experiment 16. — Several experiments were made on 

 successive guinea-pigs with the strain of B. pestis of type 

 No. 2 (derived from the Haffkine protected rat). Always, 

 however, this retained its initial attenuated or less virulent 

 character even through a succession of six guinea-pigs. 

 Every one of the animals died of the subacute disease 

 (six to twelve days) with the necrotic change in the bubo, 

 necrotic nodules in the spleen, liver, and lung. These 

 guinea-pigs had been inoculated, some cutaneously, some 

 subcutaneously, with considerable doses of the necrotic 

 tissue of the bubo (teeming with B. pestis) of a preceding 

 guinea-pig. The last of the series received subcutaneously 

 in the groin a cubic centimetre of a thick turbid emulsion 

 of the necrotic bubo of the preceding guinea-pig ; but, as 

 before, the result was the subacute disease, showing 

 necrotic bubo, and necrotic nodules in spleen, liver, and 

 lung. 



Experiment 17. — The following experiment demon- 

 strates the same result from another point of view. As 

 already mentioned, mouse 1 (B. pestis, type No. 2) died 

 in forty-eight hours from typical acute plague ; the spleen 

 was found large and crowded with B. pestis of type No. 2. 

 With a good dose — about two loops in each instance — of 

 recent agar culture of the spleen of this mouse two other 

 mice (5 and 6) were inoculated, the culture being well 

 rubbed in into several crossed incisions of the skin at the 

 roots of their tails. 



One of these mice, No. 5, died on the fifth day, the 

 other, No. 6, died on the seventh day. Both on post- 

 mortem examination showed big inguinal glands and big 



