By all means let us infer from the facts of organic evolution the conclusion that further progress must surely be possible, so much progress having already been achieved as is represented by the difference between inorganic matter or the amœba or microbe on the one hand, and man on the other hand. But let us most earnestly beware of the false and disastrous optimism which should suppose that because the survival of the fittest has often, and indeed most often, meant the survival of the best, it means always that and nothing else. On the contrary, we must learn that, even in natural circumstances, apart from any interference by man, the survival of the fittest often means racial degeneration--a tapeworm kept in spirits should stand upon the study mantelpiece of all who think with Mr. Wells that the survival of the fittest means the survival of the better; and still more notably we must learn that the interference of man in the case of his own species, sometimes of evil intent, sometimes for the highest ends, with the process of natural selection, has repeatedly led, and is now in large part leading, to nothing other than that process of racial degeneration of which the tapeworm and the barnacle should be our perpetual reminders. The case becomes serious enough when man interferes with the process of selection merely with the effect of suspending it, wholly or in part: but it becomes far more serious when his interference constitutes a reversal of the process. This most supremely disastrous of all conceivable consequences of man's intelligence and moral sense is known as reversed selection, and must be carefully studied hereafter. Meanwhile, we must devote some space to a most important consideration--namely, that though Nature is impartial in her choice, and will, for instance, allow the poisons of a microbe such as the tubercle bacillus to destroy the life of a Spinoza or a Keats or a Schubert, yet, on the whole, the survival-value of the mental, spiritual, or psychical in all its forms does persistently tend to outweigh that of the physical or material--of this great truth the evolution and dominance of man himself being the supreme example.