668. Darwin

«When on board H.M.S. 'Beagle,' as naturalist, I was much struck with certain facts in the distribution of the inhabitants of South America, and in the geological relations of the present to the past inhabitants of that continent. These facts seemed to me to throw some light on the origin of species—that mystery of mysteries, as it has been called by one of our greatest philosophers.»

Charles Darwin, in «On the Origin of Species by Means of Natural Selection, or The Preservation of Favoured Races in the Struggle for Life», 1859.