MIGRATION OF BODY-LICE 93 



In considering this last result it should be 

 borne in mind that the duration of the experi- 

 ment was only half that of the previous ones. 

 In spite of this, about half the lice migrated to 

 the neighbourhood of the second man, and the 

 biting on him commenced within an hour. Had 

 this experiment been as prolonged as were the 

 two previous ones, the result would have been 

 even more striking, while, as it was, the migra- 

 tion may have been retarded as the febrile man 

 wore a woollen undervest under his pyjamas, and 

 this was not removed as his fever was high and 

 the afternoon rather chilly. It should also be 

 noted that the fever in his case was higher than 

 in the previous ones, and in correlation with this 

 the lice showed the surprising activity referred 

 to above, and, while they fed at first when very 

 hungry, their first hunger appeased they ceased 

 to do so. In each of the other cases the primary 

 host was being bitten throughout the experiment. 



[TABLE 



