v PLAGUE IN THE EAT 123 



forty-eight hours agar subculture of the bacillus of Cardiff 

 bubo. 



Mouse 3 found dead in 40 to 44 hours. 



Mouse 4 „ „ 60 to 66 „ 



Mouse 1 died in 48 hours. 



Mouse 2 found dead in 60 to 66 hours. 



The post-mortem examination was in all four animals 

 the same : Swollen hemorrhagic inguinal glands with 

 surrounding oedema on the inoculated side ; spleen large, 

 dark, firm ; liver pale ; kidneys large, deep red. The 

 inguinal lymph glands and the spleen contained crowds of 

 B. pestis. The lymph glands were especially remarkable 

 in this respect, and later a description will be given of 

 sections made of these hardened glands. 



But though the two sets of mice showed no difference 

 as to virulence and pathology corresponding to the two 

 types of B. pestis from which the infecting material was 

 derived, the morphological and cultural distinctions 

 between B. pestis of the two types were nevertheless 

 maintained in the cultures obtained from their organs. 

 Moreover, although mice 1 and 2 died as rapidly as mice 

 3 and 4, a culture from mouse 1 when tested on a rat (1p) 

 proved of very little pathogenicity, as was described 

 above, experiment 12. 



It might of course be contended that this attenuated 

 action of the culture of the spleen of mouse 1 when 

 inoculated into rat 1p was due to the fact that possibly 

 B. pestis having passed through the mouse had as a 

 consequence become less virulent for an animal of a 

 different species, to wit the rat ; an opinion to this effect 

 has indeed been actually expressed by Calmette. I must 

 confess that I was rather surprised at Calmette's state- 



