_Charles Robert Darwin, the grandson of Erasmus Darwin, was born at Shrewsbury, England, February 12, 1809. He studied at both Edinburgh and Cambridge, and graduated from the latter in 1831. From 1831 to 1836 he served as a naturalist on the “Beagle,” which made a trip around the world in the interests of science. The voyage served as a post-graduate course for Darwin, who then first adopted his evolutionary ideas and developed as an original investigator. Reading Malthus, in 1838, on the problem of population and the food supply, he integrated Malthus’ ideas into his own views of biology. In 1844 be began his “Origin of Species,” which he completed in 1859. In 1858 he received a paper from Alfred Russell Wallace, then in the Malay Archipelago, which proposed the same theory of natural selection. Darwin believed that when organisms increased much faster than the means of subsistence, the ratios varied, and in the conditions produced by these natural causes only those organisms survived which were best fitted to their environment. He applied his concept to human evolution in his “Descent of Man,” published in 1871. He died April 19, 1882, and was buried in Westminster Abbey._ NATURAL SELECTION[32] How will the struggle for existence, briefly discussed in the last chapter, act in regard to variation? Can the principle of selection, which we have seen is so potent in the hands of man, apply under nature? I think we shall see that it can act most efficiently. Let the endless number of slight variations and individual differences occurring in our domestic productions, and, in a lesser degree, in those under nature, be borne in mind; as well as the strength of the hereditary tendency. Under domestication, it may be truly said that the whole organization becomes in some degree plastic. But the variability, which we almost universally meet with in our domestic production, is not directly produced, as Hooker and Asa Gray have well remarked, by man; he can neither originate varieties, nor prevent their occurrence; he can only preserve and accumulate such as do occur. Unintentionally he exposes organic beings to new and changing conditions of life, and variability ensues; but similar changes of conditions might and do occur under nature. Let it also be borne in mind how infinitely complex and close-fitting are the mutual relations of all organic beings to each other and to their physical conditions of life; and consequently what infinitely varied diversities of structure might be of use to each being under changing conditions of life. Can it then be thought improbable, seeing that variations useful to man have undoubtedly occurred, that other variations useful in some way to each being in the great and complex battle of life, should occur in the course of many successive generations? If such do occur, can we doubt (remembering that many more individuals are born than can possibly survive) that