Science developed when primitive man began pondering over the problems of the creation. He sought the causes of life, of the development of life forms, and the authorship or origin of the uniformity and apparent design in nature. It is, therefore, probable that what we now study as the science of organic evolution is one of the oldest of the sciences. As the ages have rolled on, the origin of life has been explained in turn by theories of: (1) eternity of present conditions; (2) miraculous creation; (3) catastrophism with (a) increases by immigration (b) increases by successive creations; and, finally, by (4) organic evolution. The term organic evolution means the forming of new combinations of the elements of organisms. It does not mean the arising of an animal or plant out of nothing--a new creation. That idea was exploded long ago. The science which Darwin started surveys the whole course of natural history in terms of four dimensions--length, breadth, depth, and duration. This was the plan which led Darwin to his great discoveries. While studying the minor changes taking place in common animals and plants, and looking over the broad vistas of nature back to the remotest times, he saw how each year countless weak and ill-adapted plants, insects, and animals were killed off. When he reflected that this process has been going on throughout all time, the idea flashed into his mind that it is through this testing ordeal that adaptability of surviving organisms is derived. One of the grandest conceptions of the human mind is that the apparently complex, inharmonic system of nature has developed from a simple beginning on a cooled globe from a jellylike cell. The theory of the permanence of species was generally held by biologists before publication of Darwin's first great book. Darwin said that no naturalist of his time doubted the accuracy of the theory of the eternity of existing conditions and they refused to listen to his views regarding the mutability of species. Darwin put forth the theory of organic evolution by natural selection and the survival of the fittest. The great beauty of this theory lies in its simplicity and its appeal to agencies which we can see in full operation every day and night. The skillful manner in which Darwin marshaled data to substantiate his theory quickly converted the scientific world, and led to revolutionary changes in the general tendencies of knowledge, and in practically all fields of human activity.