In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment.
Even when we are quite alone, how often do we think with pleasure or pain of what others think of us – of their imagined approbation or disapprobation.
Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care.
