All gentle cant and philosophizing to the contrary notwithstanding, no people in this world ever did achieve their freedom by goody-goody talk and moral suasion: it being immutable law that all revolutions that will succeed, must begin in blood.
If you invent two or three people and turn them loose in your manuscript, something is bound to happen to them -- you can't help it; and then it will take you the rest of the book to get them out of the natural consequences of that occurrence, and so first thing you know, there's your book all finished up and never cost you an idea.
What is it that strikes a spark of humor from a man? It is the effort to throw off, to fight back the burden of grief that is laid on each one of us. In youth we don't feel it, but as we grow to manhood we find the burden on our shoulders. Humor? It is nature's effort to harmonize conditions. The further the pendulum swings out over woe the further it is bound to swing back over mirth.
Mine was a trained Presbyterian conscience and knew but the one duty - to hunt and harry its slave upon all pretexts and on all occasions, particularly when there was no sense nor reason in it.
A powerful agent is the right word. Whenever we come upon one of those intensely right words in a book or newspaper the resulting effect is physical as well as spiritual, and electrically prompt.