At the outset it must be clearly understood that Darwin's doctrine is concerned primarily with the _method_ and not with the evidences as to the actual _fact_ of evolution. Most of those who are not familiar with the principles of science believe that Darwin discovered this process; but their opinion is not correct. The reality of natural change as a universal attribute of living things had been clearly demonstrated long before Darwin wrote the remarkable series of books whose influence has been felt outside the domains of biology and to the very confines of organized knowledge everywhere. The "Origin of Species" was published in 1859, and only the last of its fourteen chapters is devoted to a statement of the evidence that evolution is true. In this volume Darwin presented the results of more than twenty-five years of patient study of the phenomena of nature, utilizing the observations of wild life in many regions visited by him when he was the naturalist of the "Beagle" during its famous voyage around the world. He also considered at length the results of the breeder's work with domesticated animals, and he showed for the first time that the latter have an evolutionary significance. Because his logical assembly of wide series of facts in this and later volumes did so much to convince the intellectual world of the reasonableness of evolution, Darwin is usually and wrongly hailed as the founder of the doctrine. It is interesting to note in passing that Alfred Russel Wallace presented a precisely similar outline of nature's workings at about the same time as the statement by Darwin of his theory of natural selection. But Wallace himself has said that the greater credit belongs to the latter investigator who had worked out a more complete analysis on the basis of far more extensive observation and research. The fundamental point from which the doctrine of natural selection proceeds is the fact that all creatures are more or less perfectly adapted to the circumstances which they must meet in carrying on their lives; this is the reason why so much has been said in earlier connections regarding the universal occurrence of organic adaptation. An animal is not an independent thing; its life is intertwined with the lives of countless other creatures, and its very living substance has been built up out of materials which with their endowments of energy have been wrested from the environment. Every animal, therefore is engaged in an unceasing struggle to gain fresh food and new energy, while at the same time it is involved in a many-sided conflict with hordes of lesser and greater foes. It must prevail over all of them, or it must surrender unconditionally and die. There is no compromise, for the vast totality we individualize as the environment is stern and unyielding, and it never relents for even a moment's truce.