As in geometry the most natural way of beginning is from a mathematical point, so is the same method in observations and natural history the most genuine, simple, and instructive.

宁静的心灵是健康的源泉。

Never stop learning. The minute you think you know it all is the minute you stop growing.

We come nearest to the great when we are great in humility。

力量在于平衡：我们是我们的伤害，正如我们是我们的成功。