TRENCH FEVER 131 



human lice (Rickettsia pediculi, Rickettsia quintana, Rickettsia 

 wolhynica). 



According to Strong's (1918) experiments the virus of 

 trench fever is not transmitted by infective lice to their ova, 

 while according to a number of observers, including Bacot, 

 Rickettsia pediculi are found in the ova; a discrepancy which 

 indicates that the virus of trench fever and rickettsia are 

 separable. The positive filtration experiments of Strong with 

 trench fever virus may also be regarded as evidence contrary 

 to acceptance of rickettsia as the cause of trench fever. 



