When I want to read something nice, I sit down and write it myself.

Such is professional jealousy; a scientist will never show any kindness for a theory which he did not start himself.

Shall we go on conferring our Civilization upon the peoples that sit in darkness, or shall we give those poor things a rest?

I am pushing sixty. That is enough exercise for me.

As an example to others, and not that I care for moderation myself, it has always been my rule never to smoke when asleep, and never to refrain from smoking when awake.

Drag your thoughts away from your troubles... by the ears, by the heels, or any other way you can manage it.

Human beings can be awful cruel to one another.