CHAPTER V 
FAMILY INSTINCTS 
Ir may appear strange that instincts are first 
chosen to illustrate this Theory, for of all 
characters they are the least known or under- 
stood, and only in recent years have they been 
systematically studied, and been given an im- 
portant place among characters as a whole. 
They have been chosen because, as family 
characters, they well and clearly illustrate the 
Theory. 
The vast majority of parents have an in- 
stinct which compels them to sacrifice them- 
selves for the sake of their young; this 
sacrificing instinct is present in both sexes, 
and varies according to the age of the young. 
When the progeny is very young it is strongest, 
and as it grows older so the instinct becomes 
less strong: finally, when the progeny is full 
grown, it entirely ceases, and in many cases is 
replaced by another instinct, which compels 
the parents to drive away their progeny. The 
