36 LICE AND THEIR MENACE TO MAN 



in warm surroundings, so that- the temperature 

 outside his clothing approximates to that inside, 

 they are liable to migrate from him and pass 

 on to another near. This takes place especially 

 in beds where two people are sleeping together 

 (see Chapter VIII.). To sleep with one who is 

 infested with lice is a certain means of becoming 

 verminous. Lice, as will be shown later, are 

 also liable to leave their host when the skin 

 becomes too hot for them, as when he is in a fever. 

 They also leave at his death and scatter over his 

 bedclothes and surrounding objects, and are very 

 likely to be picked up by any one coming in 

 contact with these. They may be dislodged by 

 brushing and fall to the ground, and it has been 

 stated that they have been blown off by the 

 wind and carried to a distance. They may also 

 of their own accord leave discarded garments. 



Lice spread abroad by any of these means 

 may be termed stray lice, and they are in a very 

 helpless condition for finding fresh prey as com- 

 pared with the human flea or the bed-bug. The 

 flea jumps into the air when disturbed by a sudden 

 draught of wind, such as is caused by a foot 

 moving near it, and grasps anything it meets 

 with in its course, thus finding its temporary 

 host. The hungry bed-bug hunts down its 

 victim, probably guided by his scent, often 

 travelling long distances to find him. The stray 

 louse can only wait till a fresh host comes in 

 contact with it, or wander aimlessly about on 



