No man has a wholly undiseased mind; in one way or another all men are mad

When some men discharge an obligation you can hear the report for miles around

I, Mark Twain being of sound mind, have spent everything

A man is never more truthful than when he acknowledges himself as a liar

Age is an issue of mind over matter. If you don't mind, it doesn't matter.

I have a prodigious quantity of mind; it takes me as much as a week sometimes to make it up.