126 LICE AND THEIR MENACE TO MAN 



times recur at such regular intervals that the 

 patient can foretell his day of trouble. Every 

 fifth day the fever may return, and so we see the 

 reason for one name the Germans give to the 

 disease, but most often the periods vary and each 

 successive interval tends to become longer than 

 the last. 



Now let us turn to the louse once more and 

 see the part it plays in spreading this disease that 

 has caused so much suffering. Experiments per- 

 formed by McNee and others proved that the 

 germ of trench fever was in the blood of the 

 patient during his attacks of fever. The question 

 was, How did this germ leave the sick man and 

 enter the healthy ? Our recent work, carried out 

 for the War Office Trench Fever Research Com- 

 mittee, has done a good deal to clear this mystery 

 up. Several very gallant men came forward to 

 help us in our task, and it is not too much to say 

 that without such help we would have found out 

 nothing, since experimental animals, which are all 

 apparently resistant to trench fever infection, 

 could not be used. These men volunteered to 

 let us try to give them trench fever in any way 

 we thought the disease might spread naturally in 

 the field. The first two men to come forward 

 were W. H. Cole and H. H. Edgeler, and to them 

 great credit is due, as the work for which they 

 offered themselves might, for all they knew, be 

 productive of most unpleasant consequences. 

 Attempts were made to convey trench fever to 



