MIGRATION OF BODY-LICE 99 



febrile condition of the primary host nearly 

 doubled the migration. Where the primary host 

 was febrile the second man felt the biting of the 

 lice very much earlier than in the other cases, 

 so soon, in fact, that it is indicated that some 

 of the lice migrated either before they had fed 

 on the febrile man, or at any rate before they 

 had obtained a full meal. Where the first man 

 was normal the interval before the second was 

 bitten was such as to have allowed them to be 

 ready for a second meal after having fed to 

 temporary repletion when first released. 



Conclusion. The temperatures attained in the 

 sufferers from the three diseases carried by lice 

 and characterised by a febrile condition are : 

 typhus fever 103-104, sometimes 105; re- 

 lapsing fever 104-105 usually ; trench fever 

 commonly 103 and often 104. It may there- 

 fore be taken as proven that the fevers of these 

 maladies tend to increase greatly the shedding 

 of the lice from the patients, quite apart from 

 their deaths, and that this phenomenon is partly 

 accountable for the rapidity with which louse- 

 borne epidemics spread. 



