268 KATHARINE FOOT. 



kept of the behavior of the lice being thus fed on presumably 

 medicated blood. 



By this method three drugs were tested, Quinine, potassium 

 iodid and sodium salicylate. 1 Of these three drugs quinine 

 (which was suggested by Dr. Alexander Lambert) caused ap- 

 parently the most abnormal response. As stated in my report 

 " biting during the hour was less frequent and for much shorter 

 periods. The nymphs were very restless, making frequent efforts 

 to escape under the edge of the glass ring in which they were 

 confined." I concluded my report as follows: "Although the lice 

 do not bite normally and do not reproduce normally the toxic 

 effect of the quinine is not sufficiently injurious to eliminate them. 

 The most promising result is the very evident effort of the young 

 nymphs to escape and in view of the well-known and persistent 

 assertion that lice avoid some healthy people and leave hosts who 

 have contracted certain diseases, it is possible that this effort to 

 escape may indicate a distaste of the blood which may cause lice 

 to leave a host who is taking quinine." 



Potassium Iodid. The experiment with this drug (appendix, 

 p. 273) was less promising than the quinine experiment, the lice 

 showing no desire to escape they did however attack one an- 

 other during the feeding hour, this presumably being an expres- 

 sion of some discomfort. The results from this experiment as 

 stated in my report are as follows: "The only abnormal feature 

 in the life history of two generations of lice was the marked 

 tendency of the first generation to attack one another during the 

 feeding hour. There is no evidence that potassium iodid taken 

 by the host is either injurious or distasteful to the lice." 



Sodium Salicylate. The experiment with sodium salicylate 

 (appendix, p. 274) was of interest merely because the sexes of 

 the generation which was raised from four pairs of lice was 

 most unequal, showing a very small proportion of males. These 

 results would be of interest if the sexes are normally equal but 

 this is an open question in view of Hindle's conclusions as to 

 their normal variable inequality. Nuttall ('17) in giving a sum- 

 mary of the data as to the sexes says " the proportion of the 

 sexes as determined by raising experiments have yielded contra- 



i See appendix, page 272, for brief records of these three experiments. 



