120 RICKETTSIA 



to this micro-organism. He called attention to differences 

 between rickettsia and bacteria. He discovered that a temper- 

 ature above 23 C. was necessary for the development of 

 rickettsia in lice and recommended 32 C. as the optimum 

 temperature. A period of at least five days is required for the 

 development in lice to reach a demonstrable stage. 



Noller (1916), in a few experiments with lice, confirmed 

 da Rocha-Lima's observations in regard to the appearance of 

 rickettsia in lice fed upon typhus patients. 



Topfer and Schtissler (1916) reported results confirming da 

 Rocha-Lima's in regard to the occurrence and intracellular 

 position of rickettsia in lice fed upon typhus patients. They 

 did not find them in lice from healthy individuals or from 

 patients with other diseases. For their material lice collected 

 from typhus cases were used as well as lice experimentally fed 

 upon patients. No infected lice were found before the fourth 

 day while after the ninth day all were found infected. The 

 illustrations and descriptions given correspond with those of 

 da Rocha-Lima. 



Topfer (1916) later reported work based upon the examina- 

 tion of more than five thousand lice, examined mostly by 

 means of smear preparations but also by sectioning. He did 

 not agree with da Rocha-Lima in separating rickettsia from 

 bacteria and regarded them as identical with the cocco- 

 bacilli described by Sergent, Foley, and Vialette and main- 

 tained that he could not discover notable differences in their 

 staining reactions as compared with bacteria. The type form 

 of rickettsia he regarded as a bacillus and the other forms 

 described, as stages in division and growth. Topfer also could 

 not confirm von Prowazek's conclusions in regard to the paired 

 granules in neutrophilic leucocytes in typhus, as he also found 

 indistinguishable appearances in leucocytes from other febrile 

 conditions. He called attention to the fact that saprophytic 

 bacteria could multiply within cells in the louse. However, 

 Topfer unreservedly concludes from his own investigations 

 that this micro-organism is the cause of typhus, and in all 



