PROTOCOLS OF EXPERIMENTS 73 



Record of Guinea-pig 12, inoculated with rickettsia-free 

 louse W 216 



At no time during an observation period of thirty-eight days 

 did this guinea-pig's temperature exceed normal limits. On 

 June 22d it was inoculated intraperitoneally with 5 c.c. of 

 blood from patient 799 (eighth day of typhus) as a test for 

 immunity. The temperatures subsequent to this inoculation 

 were: 



F. F. 



June 22 No record July 5 106.8 



23 103.4 " 6 No record 



24 No record 7 103.8 



25 102.2 8 103.8 



26 No record " 9 No record 



27 102.0 10 103.1 



28 102.1 11 102.4 



29 No record 12 102.8 



30 102.2 13 102.7 



July 1 104.0 " 14 102.4 



" 2 No record " 15 No record 



" 3 103.8 16 102.1 



" 4 105.9 17 102.6 



July 17th; killed. The spleen was slightly enlarged; no other 

 lesions found. 



Result: Guinea-pig 12, inoculated with the viscera of ricket- 

 tsia-free louse W 216, did not develop typhus in an incubation 

 period of thirty-eight days. It proved susceptible to an inocu- 

 lation of human blood on June 22d, developing typhus after a 

 further observation period of nine days. 



Conclusion: Rickettsia-free louse W 216 did not contain the 

 virus of typhus. 



