"As Virtue, says Plato, is the Health of a strong and vigorous Mind, so Vice is the Disease of weak and imperfect one; and 'tis the Habitude which renders either of a Piece with the Soul, and becomes a kind of second Nature."
An Index to Mankind: or Maxims Selected from the Wits of all Nations 
An Index to Mankind: or Maxims Selected from the Wits of all Nations (Dublin: James Hoey, 1765). &lt;<a href="http://books.google.com/books?id=5JUDAAAAQAAJ">Link to Google Books</a>&gt;