PROTOCOLS OF EXPERIMENTS 83 



July 17th; killed, owing to departure from Paris. The au- 

 topsy showed an enlarged spleen and no other lesions. No 

 histological examination was made, as the tissues were lost. 



Result: Guinea-pig 30, inoculated with rickettsia-free louse 

 W 266 did not develop typhus during an observation period of 

 thirty-seven days. Following an inoculation with human 

 typhus blood, it apparently reacted positively after a further 

 observation period of twenty-three days. 



Conclusion: Rickettsia-free louse W 266 probably did not 

 contain the virus of typhus. 



Record of Guinea-pig 31, inoculated with the viscera of 

 rickettsia-free louse W 267 



The temperatures following inoculation on May 16th were 

 as follows: 



F. F. 



May 16 102.0 May 27 101.2 



17 102.8 



18 102.7 



19 102.4 



20 . . 102.6 



21 102.5 June 1 104.0 



22 102.2 



23 102.3 



24 102.9 



25 102.7 



26 . . 102.2 



28 101.8 



29 102.4 



30 102.7 



31 . . 104.0 



2 102.8 



3 102.2 



4 102.4 



5 103.6 



6 . . Dead 



The autopsy showed acute pneumonia of both lungs, acute 

 endocarditis, and acute peritonitis. 



Result: Guinea-pig 31 failed to develop typhus during the 

 period of observation of twenty days, terminated by an acute 

 infection. 



Conclusion: Rickettsia-free louse W 267 probably did not 

 contain the virus of typhus. 



