Natural selection, it should never be forgotten, can act solely through and for the advantage of each being.

永远不要忘记， 自然选择可以完全通过并为每个生物的利益而行动。

He could feel only the sense of satisfaction at seeing the diplomatic triumph of all his family, since the breed existed, at last realized under his own eyes for the advantage of his oldest and closest ally.

看到他所有家族的外交胜利，他只能感到满足感，因为这个品种的存在，终于在他眼皮底下实现了他最年长和最亲密的盟友的利益。