Second lecture on discoveries and inventions, delivered to the Phi Alpha Society of Illinois College at Jacksonville, Illinois, (February 11, 1859); "The Collected Works of Abraham Lincoln, Vol. 3" edited by Roy P. Basler, (p. 357), 1953.
Walter Bagehot (1999). “Physics and Politics, Or, Thoughts on the Application of the Principles of "natural Selection" and "inheritance" to Political Society”, Ivan R Dee