How often it turns out that a man's minor works outlive his major! This is true in both literature and science, but more often in the former than in the latter. Darwin furnishes a case in the field of science. He evidently looked upon his "Origin of Species" as his great contribution to biological science; but it is highly probable that his "Voyage of the Beagle" will outlast all his other books. The "Voyage" is of perennial interest and finds new readers in each generation. I find myself re-reading it every eight or ten years. I have lately read it for the fourth time. It is not an argument or a polemic; it is a personal narrative of a disinterested yet keen observer, and is always fresh and satisfying. For the first time we see a comparatively unknown country like South America through the eyes of a born and trained naturalist. It is the one book of his that makes a wide appeal and touches life and nature the most closely. We may say that Darwin was a Darwinian from the first,--a naturalist and a philosopher combined,--and was predisposed to look at animate nature in the way his works have since made us familiar with. In his trip on the Beagle he saw from the start with the eyes of a born evolutionist. In South America he saw the fossil remains of the Toxodon, and observed, "How wonderful are the different orders, at the present time so well separated, blended together in the different points of the structure of the Toxodon!" All forms of life attracted him. He looked into the brine-pans of Lymington and found that water with one quarter of a pound of salt to the pint was inhabited, and he was led to say: "Well may we affirm that every part of the world is habitable! Whether lakes of brine or those subterranean ones hidden beneath volcanic mountains,--warm mineral springs,--the wide expanse and depth of the ocean,--the upper regions of the atmosphere, and even the surface of perpetual snow,--all support organic beings." He studies the parasitical habit of the cuckoo and hits on an explanation of it. He speculates why the partridges and deer in South America are so tame.