I must have a prodigious quantity of mind; it takes me as much as a week, sometimes, to make it up.
Source: The Innocents Abroad, ch. 7, 1869.
-- Mark Twain, (Nov 30 1835-1910), US novelist, journalist, river pilot; The Great American humorist was also known as The People's Author and creator of Tom Sawyer and Huck Finn.