PROTOCOLS OF EXPERIMENTS 



103 



tion period of twenty-eight days, following an inoculation 

 with human blood on June 28th, it failed to react, although 

 on July 13th and 14th there was a slight rise of temperature 

 coincident with the onset of typhus in other guinea-pigs re- 

 ceiving the same blood oil the same date. 



Conclusion: Louse 4 of Box xxxvn probably did not con- 

 tain the virus of typhus. 



Experiments with Box XXXVIII lice 



Between feedings the box was kept in an incubator at a 

 temperature varying from 20 to 30 C., usually 29 C. The 

 box contained 30 W lice (30 nymphs). 



From these lice the following preparations were made: 



Louse No. 



Smears 1 

 2 



Result of Microscopical 

 Examination 



Rickettsia absent 

 Rickettsia absent 



3 



4 



Excreta 



Dead red male 



Rickettsia present 



absent 

 present 



Result of Animal Inoculation 



Guinea-pig 45; Temp. 

 Guinea-pig 46; Temp. + 

 Lesions present 

 Guinea-pig 47; Temp. + 

 Guinea-pig 48; Temp. + 



