He who is fixed to a star does not change his mind.

Every obstacle yields to stern resolve.

It is no small benefit on finding oneself in bed in the dark to go over again in the imagination the main lines of the forms previously studied, or other noteworthy things conceived by ingenious speculation.

One day the world will look upon research upon animals as it now looks upon research on human beings.

Beyond a doubt truth bears the same relation to falsehood as light to darkness.

Men born in hot countries love the night because it refreshes them and have a horror of light because it burns them.

I am still hopeful. A falcon, Time. But the coincidence is probably accidental.