84 



SPECIFICITY OF RICKETTSIA PROWAZEKI 



Experiments with Box XXVIII lice 



Between feedings the box was kept in an incubator at a tem- 

 perature varying from 20 to 25 C. The box contained SOW 

 lice (30 larvae). 



From these lice the following preparations were made: 



Result of Animal Inoculation 



Louse No. 



Smears 



I 



II 



III 



IV 



Smear of egg 

 Smear of excreta 

 Smear of excreta 



Result of Microscopical 

 Examination 



Rickettsia absent 



u u 



