v PLAGUE IN THE EAT 121 



kidneys large, congested. No cultures were obtained 

 from either the inguinal glands, the spleen, or the heart's 

 blood. 



This experiment shows conclusively the attenuated, less 

 virulent condition of the type 2, and contrasts strongly 

 with the action of a parallel culture of the type 1. Be it 

 remembered that rat In was inoculated with a subculture 

 (second remove) from the spleen of a rat (11), which rat 

 had died of acute plague, caused by inoculation with the 

 B. pestis of the second type. 



It follows from these experiments that after passing 

 through a succession of rats B. pestis of the type 2 retained 

 its attenuated action unimpaired. 



The above are not by any means the only experiments 

 which I have made on rats with active cultures, twenty- 

 four hours and forty-eight hours old agar cultures, of the 

 (transparent) strain (type 2). Thus, I have records of 

 rats lo, 1p, Iq, 1r. 



Experiment 11. — Eat lo was inoculated cutaneously 

 with the growth of a forty-eight hours agar subculture 

 from rat 1l. 



Experiment 12. — Eat 1p with forty -eight hours 

 culture from the spleen of a mouse dead within forty- 

 eight hours after cutaneous inoculation with same strain 

 (see later), cutaneously. 



Experiment 13. — Eat Iq with a twenty -four hours 

 old agar subculture from rat 1l, cutaneously. 



Experiment 14. — Eat 1r with a twenty -four hours 

 old agar subculture (second remove) from spleen of rat Iq, 

 subcutaneously. 



In all the cases where inoculation was practised 

 cutaneously a fair-sized particle of the growth was well 



