64 SPECIFICITY OF RICKETTSIA PROWAZEKI 



guinea-pig developed a temperature consistent with typh'ds in- 

 fection, after a period of ten days. This probably indicates a 

 susceptibility of this guinea-pig to typhus. 



Conclusion: Rickettsia-free louse W 225 probably did not 

 contain the virus of typhus. 



Record of Guinea-pig 10, inoculated with viscera from 

 rickettsia-free louse W 226 



The temperatures following inoculation on May 15th showed 

 rises on May 18, 19, 24, and 25, and June 18, to 103.5F. or 

 higher, but upon intervening days was within normal limits. 

 On June 22, after an observation period of thirty-eight days, 

 the guinea-pig was inoculated intraperitoneally with 5 c.c. of 

 blood from patient 799 and the temperatures subsequently were 

 as follows: 



F. F. 



June 22 No record July 5 105.7 



23 103.6 6 No record 



24 . . No record * 7 . .No record 



25 102.3 



26 No record 



27 102.2 



28 102.3 



29 No record 



30 102.4 



July 1 103.2 



2 No record 



3 . . 104.3 



8 104.9 



9 No record 



10 104.1 



11 104.2 



12 103.8 



13 102.0 



14 102.1 



15 No record 



16 . . 102.1 



4 105.4 " 17 101.6 



June 17th; killed. The autopsy showed a slightly enlarged 

 spleen. Other tissues were negative except for cicatrices in 

 liver and omentum. 



Result: Rickettsia-free louse W 226 did not transmit typhus 

 to guinea-pig 10 during an observation period of thirty-eight 

 days. After inoculation with blood from a typhus patient this 

 guinea-pig developed typhus, after a further observation period 

 of eleven or twelve days, thereby proving the susceptibility of 

 this guinea-pig. 



Conclusion: Rickettsia-free louse W 226 did not contain the 

 virus of typhus. 



