92 



SPECIFICITY OF RICKETTSIA PROWAZEKI 



July 17th; killed. The autopsy showed no lesions. The 

 tissues were lost, and no histological examination could be 

 made. 



Result: Guinea-pig 37, following inoculation with the viscera 

 of louse 2 of Box xxxiv, did not develop typhus during an ob- 

 servation period of thirty-eight days. 



Following an injection of human typhus blood, after an in- 

 cubation period of sixteen days, it developed temperatures 

 consistent with typhus. 



Conclusion: Rickettsia-free louse 2 of Box xxxiv did not 

 contain the virus of typhus. 



Record of Guinea-pig 38, inoculated with the viscera of 

 louse 3 of Box XXXIV 



The temperatures following the inoculation on May 22d 

 were as follows: 



June 10 103.0 



11 102.0 



12 102.2 



13 102.4 



14 103.0 



15 103.6 



16 103.4 



17 103.0 



18 102.6 



19 102.9 



20 No record 



21 104.2 



22 No record 



23 103.6 



24 No record 



25 103.6 



26 No record 



27 . . 103.8 



On June 28th this guinea-pig was inoculated intraperitone- 

 ally with 5 c.c. of blood from patient 814 (eighth day of typhus). 

 The subsequent temperatures were as follows: 



