INFECTION OF GUINEA PIGS, MONKEYS, AND RATS. 253 



Table II. — Guinea piga and plague straiyi "Shanghai." 



Dose in numbtir uf bacilli. 



Number 

 of animals 

 inocu- 

 lated. 



Result. 



Infected 

 and died. 



Infected 



and 



recovered. 



Not 

 infected. 



Number 

 of days 

 between 

 inocula- 

 tion and 

 death. 



1 



1 

 6 

 1 

 1 

 1 

 3 







1 

 

 1 

 



1 





 

 

 () 



1 

 2 



1 

 5 

 1 

 

 

 





2 to 10 



14 



U to50 



51 to 100 



12 



101 to 200 



201 to 600 



8 



Total 



13 



3 



3 



7 









Table III. — Monkeys and virulent plague. 



Dose in number of bacilli. 



Number 

 of animals 

 inocu- 

 lated. 



Results. 



Infected 

 and died. 



Infected ^^^ 

 recovered, -^-^ed. 



1 



Number 



of days 



between 



inoculation 



and death. 



1 



12 

 10 

 4 

 2 

 3 



2 



1 

 1 

 2 

 



10 



8 and 15 



17 



5 



20 and 9 



2 to 10 





 

 



n 



9 

 3 





 R 



11 to 50 



101 to200. 



201 to 500 



Total - 







31 



6 



2.«; 













Table IV. — Rats and virulent plague. 



Dose in number of bacilli. 



Number 

 of animals 

 inocu- 

 lated. 



Results. 



Infected 

 and died. 



Infected 



and 

 recovered. 



Not 

 infected. 



1 



Number 



of days 



between 



inoculation 



and death. 



1 



2 

 7 

 4 

 1 





 2 

 2 

 





 

 

 



2 

 5 

 2 

 1 





2tol0 



9 and 13 

 9 and 19 



lltoSO 



51 to 100 



Total 







14 



4 







10 









It will be noticed from Table I that the percentage of fatal 

 infections in the guinea pigs receiving a dose of one bacillus of 

 the virulent strain is nearly the same as that of the entire 36 

 which received 1 to 500 ; namely, 63.9 per cent and 66.7 per cent 

 respectively. 



