life-forms, and of the laws and forces on which these changes depend. Even as thus restricted organic evolution, or bionomics, is the greatest of the sciences, including in its subject-matter, not only all natural history, not only processes like cell-division and nutrition, not only the laws of heredity, variation, natural selection, and mutual help, but all matters of human history, and the most complicated relations of civics, economics, or ethics. In this enormous science no fact can be without a meaning, and no fact or its underlying forces can be separated from the great forces whose interaction from moment to moment writes the great story of life. And as the basis to the science of bionomics, as to all other science, must be taken the conception that nothing is due to chance or whim. Whatever occurs does so as the resultant of moving forces. Could we know and estimate these forces, we should have, so far as our estimate is accurate and our logic perfect, the gift of prophecy. Knowing the law, and knowing the facts, we should foretell the results. To be able in some degree to do this is the art of life. It is the ultimate end of science, which finds its final purpose in human conduct. "A law," according to Darwin, "is the ascertained sequence of events." The necessary sequence of events it is, in fact, but man knows nothing of what is necessary, only of what has been ascertained to occur. Because human observation and logic can be only partial, no law of life can be fully stated. Because the processes of the human mind are human, with organic limitations, the study of the mind itself becomes a part of the science of bionomics. For it is itself an instrument or a combination of instruments by which we acquire such knowledge of the world outside of ourselves as may be needed in the art of living, in the degree in which we are able to practise that art. The necessary sequence of events exists, whether we are able to comprehend it or not. The fall of a leaf follows fixed laws as surely as the motion of a planet. It falls by chance because its short movement gives us no time for observation and calculation. It falls by chance because, its results being unimportant to us, we give no heed to the details of its motion. But as the hairs of our head are all numbered, so are numbered all the gyrations and undulations of every chance autumn leaf. All processes in the universe are alike natural. The creation of man or the growth of a state is as natural as the formation of an apple or the growth of a snow-bank. All are alike supernatural, for they all rest on the huge unseen solidity of the universe, the imperishability of matter and the immanence of law.