RELATION TO OTHER ANIMALS 157 



ships, or prisons, and specific irritations known as 

 Pediculosis and Phthiriasis are produced by them. 

 It has been calculated that a single adult female of 

 the body louse might have, in eight weeks, a progeny 

 of 5000, and while this is not equal to the performances 

 of some other insects it does, nevertheless, serve to 

 make possible a very rapid and complete infestation 

 where they are allowed to develop unchecked. 



Of course personal cleanliness is the best of all 

 methods to be and become free from such parasitism; 

 but infestation in modern conveyances is always pos- 

 sible, and with even the greatest care a parasite may 

 obtain a foothold. Children, who are not always choice 

 in their companions, not infrequently become infested 

 by head lice. A fine-tooth comb and a thorough greas- 

 ing of the hair with pomade or any fatty material, 

 repeated twice at intervals of a week each, will clear 

 out the parasites. The grease enters into and clogs 

 the breathing pores of the lice and chokes them; but 

 it does not affect the eggs or -'nits." The later 

 applications are intended to reach the young that 

 have hatched from the eggs since the previous ones. 

 As the eggs may remain unhatched for ten days or 

 two weeks, this period of time will be necessary to 

 insure freedom. 



As for the body louse, the infested clothing should 

 be discarded for a time. Underclothing may be sub- 

 jected to lengthy boiling to kill both adults and eggs. 

 Outer garments should be steamed or baked if possible, 

 or should be dipped into gasoline; this latter applica- 

 tion to be repeated in ten 'days, to reach later hatchings. 

 The gasoline process is simplest as it kills all the adults 

 at once, and if it can be repeated at short intervals, 

 the clothing can be worn in the periods between 

 treatments. 



