H. G. Wells,
The Outline of History: Being a Plain History of Life and Mankind
“ Conquering people have also, and especially when there were marked physical differences of race, been disposed to keep themselves aloof from the conquered peoples, and have developed an aristocratic exclusiveness. Such organizations of restriction upon free intercourse have come and gone in great variety in the history of all long-standing civilizations. The natural boundaries of function were always there, but sometimes they have been drawn sharply and laid stress upon, and sometimes they have been made little of. ”
