science, I fear that to some of you I must in many places have been very hard to follow. But as a general outcome of the whole lecture—as the great and vivifying principle by which all the facts are more or less connected, and made to spring into a living body of philosophic truth—I will ask you to retain in your memories one cardinal conclusion. We are living in a generation which has witnessed a revolution of thought unparalleled in the history of our race. I do not merely allude to the fact that this is a generation in which all the sciences, without exception, have made a leap of progress such as widely to surpass all previous eras of intellectual activity; but I allude to the fact that in the special science of biology it has been reserved for us to see the first rational enunciation, the first practical demonstration, and the first general acceptance, of the doctrine of evolution. And I allude to this fact as to a fact of unparalleled importance in the history of thought, not only because I know how completely it has transformed the study of life from a mere grouping of disconnected observations to a rational tracing of fundamental principles, but also because it is now plainly to be foreseen that what the philosophy of evolution has already accomplished is but an earnest of what it is destined to achieve. We know the results which have followed in the science of astronomy by the mathematical proof of the law of gravitation; and can we doubt that even more important results will follow in the much more complex science of biology from the practical proof of the law of evolution? I at least can entertain no doubt on this head; and, forasmuch as this enormous change in our means of knowledge and our modes of thought has been so largely due to the almost unaided labors of a single man, I do not hesitate to say, even before so critical an audience as this, that in all the history of science there is no single name worthy of a veneration more profound than the now immortal name of Charles Darwin.
Do you ask me why I close this lecture with such a panegyric on the philosophy of evolution? My answer is: If we have found that in the study of life the theory of descent is the key-note by which all the facts of our science are brought into harmonious relation, we cannot doubt that in our study of mind the theory of descent must be of an importance no less fundamental. And, indeed, even in this our time, which is marked by the first opening dawn of the science of psychology, we have but to look with eyes unprejudiced to see that the philosophy of evolution is here like a rising sun of truth, eclipsing all the lesser lights of previous philosophies, dispelling superstitions like vapors born of darkness, and revealing to our gladdened gaze the wonders of a world till now unseen. So that the cardinal conclusion which I desire you to take away, and to retain in your memories long after all the lesser features of this discourse shall have faded from your thoughts, is the conclusion that mind is everywhere one; and that the study of comparative psychology, no less than the study of comparative anatomy, has hitherto yielded results in full agreement with that great transfor-
