12s2a24 In this, in other fields. We shall our subject best uwe begin at the be rd consider there must necessarily be a union br pairing of those who cannot exist without one another l Male and female must unite for the reproduction of the species not from deliberate intention, but from the natural impulse, which exists in animals generally as it also exists in plants, to leave behind them something of the same nature as themselves Next, there must necessarily be union of the naturally ruling element with the element which is naturally ruled, for the preservation of bothl The element which is able, by virtue of its intelligence, to exercise thought, is naturally a ruling and master nlement: the element which is able ny virtue of its bodil to do the physical work, is a rule i elen it, wh s natu in a state avery, and master and slave have a ingly common interest