S50 AFTER A. 
geny amounted to fifty, and they grew so 
rapidly, and so soon produced another 
generation, that he calculated, that one 
female might, in the space of eight 
weeks, have five thousand descendants. 
Lucy, What an amazing increase ! I 
wonder how any body can be free from 
them. 
Mother. Constant cleanliness is the 
grand preservative. These insects breed 
chiefly in the head, because the moisture 
and warmth, which is usually found under 
the hair, is particularly suitable to their 
habits. When they first issue from the 
^^^ they are nearly white ; but as they 
grow, and change their skins, they be- 
come of a dark grey tint. The head ter- 
minates in a sort of hollow snout, or 
sheath, containing a trunk, or sucker, 
which is said to be seven hundred times 
less than a common hair, and through 
which all their food is imbibed. 
Lucy, It feeds only upon blood, I 
suppose ? 
Mother. Blood is its chief food, and 
