innumerable foes, finds itself involved in a warfare that is tragically one-sided; and it must prevail over all its many foes or it must acknowledge defeat and pay the penalty for unconditional surrender, which is death—so stern and unyielding is that vast totality we individualize as the environment. The generalized biological formula, then, for the turmoil of nature is adaptation = life.
Here, then, is the heart of the mystery. How has this universal condition of adaptation been brought about? What have animals within them that might determine their greater or less efficiency? What external influences, if any, are capable of directing the efforts of living creatures to meet their enemies? How are modifications perpetuated when they have arisen? To many of these questions Darwin, Weismann, Mendel, De Vries and others have found answers, not complete or perfect, it is true, but they have relegated to the past the former reply that supernatural causes must be invoked to account for nature. Science is convinced that the study of nature's workings at the present time reveals natural factors which are competent to account for much of the wonderful process of evolution.
As every one knows, the works of Darwin inaugurated our recent era in biology. In 1858, Darwin and Wallace announced the doctrine of natural selection, and, in 1859, Darwin published the "Origin of Species," a book that has proved a veritable Magna Charta of intellectual liberties, for as no other single document before or since it has released the thoughts of men from the trammels of unreasoned conservatism and dogmatism. And its influence has been felt far beyond the borders of biological science—it has extended to the very confines of organized knowledge everywhere. But it is a mistaken popular notion, and one of the hardest to drive from the mind of the layman in science, that Darwin founded the doctrine of evolution by the book mentioned and those that followed. The fact of evolutionary descent had been established long before, while even some of the special points of Darwin's theories as to method had been anticipated. Had Darwin never lived, I believe that evolution would still be accepted and taught at the present day. But Darwin rendered two immortal services to science. During the twenty years that elapsed between the first conception of his theories and the date of their publication, he marshalled in orderly array all the biological data obtainable which proved the transformation of species, including the previously unrecognized body of evidence afforded by the domesticated animals. In the second place, in his doctrine of natural selection he presented for the first time a partial consistent program of nature's method of accomplishing evolution. Darwin did not believe that this explanation was final or even complete, whatever his opponents of the time or critics of the present might contend.