2/8 KATHARINE FOOT. 



2 5$). They are full of blood and apparently normal, and this 

 evidence that the blood is not digested is apparent in nearly all 

 the lice that have died. 



Behavior while Feeding. All fed normally. 



September 17: One dead (a <$}. He was full of blood and 

 apparently normal. 



Behavior while Feeding. The older lot fed quietly but took 

 scarcely any blood. The one hatched September n was very 

 restless and took no blood. 



September 18: Two dead (both <&?). They were full of blood 

 and apparently normal. 



Behavior while Feeding. The older lot fed normally. The 

 one hatched September II ran around for 45 minutes and then 

 fed normally. 



September 19: The one hatched September n is dead (a <^). 

 He had digested some of the blood taken yesterday and appeared 

 normal. 



Behavior while Feeding. One did not bite, the balance fed 

 normally. 



Results. 



The death rate for the ten days feeding is certainly abnormally 

 high. Of the 36 used for the experiment, 26 died and as most of 

 these died before the second moult, and several died while moult- 

 ing, the facts seem to indicate that Du R.'s blood does not nour- 

 ish the lice normally but it does not warrant assuming that it 

 adequately explains his apparent immunity. The proportion of 

 the sexes of those that died was 17 <$<$ and 9 $$. 



The second question "Is biting followed by itching ?" can 

 be answered conclusively, for the itching was absolutely normal 

 and very distressing. This proves that his immunity was not a 

 case of being deceived by the fact that biting was not followed 

 by itching. 



The third question " Is there evidence that Du R.'s skin is 

 abnormally thick?" can also be answered conclusively. The 

 lice had no difficulty in drawing blood and even the nymphs just 

 emerged from the shell, bit at once and fed normally. The lice 

 were fed on various areas of the arm from the wrist to the 



