It was all love on my side, and all good comradeship and friendship on hers. When we parted she was a free woman, but I could never again be a free man.

It is, I admit, mere imagination; but how often is imagination the mother of truth?

Our ideas must be as broad as Nature if they are to interpret Nature.

The world is full of obvious things which nobody by any chance ever observes.

Might I trouble you to open the window, for chloroform vapour does not help the palate.

His incredible untidiness, his addiction to music at strange hours, his occasional revolver practice within doors, his weird and often malodorous scientific experiments, and the atmosphere of violence and danger which hung around him made him the very worst tenant in London.

I have mastered the principles of several religions. They have all shocked me by the violence which I should have to do to my reason to accept the dogmas of any one of them.