PROTOCOLS OF EXPERIMENTS 65 



Record of Guinea-pig 9, inoculated with the viscera of 

 rickettsia-free louse W 227 



The temperatures subsequent to inoculation on May 15th 

 were as follows: 



F. F. 



May 15 102 4 May 23 104.4 



" 16 102.1 24 104.5 



" 17 No record " 25 103.9 



" 18 103.0 26 103.8 



19 105.4 27 104.0 



" 20 104.4 28 103.0 



" 21 104.4 29 102.0 



22 104.8 



From May 29th to June 22d the temperatures remained 

 within normal limits. On June 22d this guinea-pig 9 received 

 intraperitoneally 5 c.c. of blood from typhus patient 799 

 (eighth day of disease). No rise of temperature followed (ex- 

 cept on July 3d when it rose to 104.5F. in common with that 

 of all other guinea-pigs on the first day of transit in an over- 

 heated freight car) during a further observation period of 

 twenty-five days. 



Result: Guinea-pig 9, inoculated with viscera from rickettsia- 

 infected louse W 227 developed typhus after an incubation 

 period of four or five days. It proved later to be immune to 

 blood from a typhus patient which was infectious for other 

 guinea-pigs. An autopsy on July 18th gave completely nega- 

 tive results. No histological examination was made. 



Conclusion: Rickettsia-infected louse W 227 contained the 

 virus of typhus. 



