Henry David Thoreau (2014). “Citizen Thoreau: Walden, Civil Disobedience, Life Without Principle, Slavery in Massachusetts, A Plea for Captain John Brown”, p.197, Graphic Arts Books
'Hansard' 17 March 1845, col. 1028. Bagehot, quoting Disraeli in 'The English Constitution' (1867) 'The House of Lords', elaborated on the theme with the words 'so much did the ideas of its "head" differ from the sensations of its "tail".'