TYPHUS FEVER 111 



An investigation into the possible association 

 of body-lice with typhus was made by three 

 French doctors, Nicolle, Blaizot, and Conseil. 

 Body-lice were fed on men and monkeys suffering 

 from typhus, and after a period of a week, during 

 which the virus was developing in them, they 

 were found capable of infecting, by means of 

 their bites, other monkeys on which they were 

 then fed. It was also shown that if the gut con- 

 tents of such infected lice were removed and 

 spread over a scratched area of skin on a healthy 

 monkey, it developed the disease. It was further 

 proved that if the excreta of the infected lice 

 were collected and inoculated by scratching, an 

 attack of the disease followed. Head-lice equally 

 with body-lice are able to transmit the malady. 

 It would appear that the offspring of the in- 

 fected lice are not, as in relapsing fever they are, 

 themselves able to hand on the disease, though 

 this is still disputed, one experiment having 

 had a positive result and many negatives being 

 required to discredit one positive. 



As soon as this association between lice and 

 typhus fever was proved, all that was known 

 about the spread of the disease fell into line. The 

 theory most popularly held had been that the 

 virus was air-borne, but that a short passage 

 through air sufficed to kill it, a close approxima- 

 tion of the healthy to the infected person being 

 therefore necessary. It was now seen why in 

 times past doctors and nurses were so liable to 



