That part [of my work] which is done while I am sleeping is the Brownies' part beyond contention; but that which is done when I am up and about is by no means necessarily mine, since all goes to show the Brownies have a hand in it even then. Slight and imperfect as the above statistics and observations admittedly are, they seem to me to point in a more useful direction than do some of the facts collected by that modern group of anthropologists who hold that genius is in itself a kind of nervous malady, a disturbance of mental balance, akin to criminality or even to madness. It is certainly not true, as I hold, either that the human race in general is nervously degenerating, or that nervous degeneration tends to a maximum in its most eminent members. But it can be plausibly maintained that the proportion of nervous to other disorders tends to increase. And it is certain that not nervous degeneration but nervous change or development is now proceeding among civilised peoples more rapidly than ever before, and that this self-adaptation to wider environments must inevitably be accompanied in the more marked cases by something of nervous instability. And it is true also that from one point of view these changes might form matter for regret; and that in order to discern what I take to be their true meaning we have to regard the problem of human evolution from a somewhat unfamiliar standpoint. The nervous system is probably tending in each generation to become more complex and more delicately ramified. As is usual when any part of an organism is undergoing rapid evolutive changes, this nervous progress is accompanied with some instability. Those individuals in whom the hereditary or the acquired change is the most rapid are likely also to suffer most from a _perturbation which masks evolution_--an occasional appearance of what may be termed "nervous sports" of a useless or even injurious type. Such are the fancies and fanaticisms, the bizarre likes and dislikes, the excessive or aberrant sensibilities, which have been observed in some of the eminent men whom Lombroso discusses in his book on the Man of Genius. Their truest analogue, as we shall presently see more fully, lies in the oddities or morbidities of sentiment or sensation which so often accompany the development of the human organism into its full potencies, or precede the crowning effort by which a fresh organism is introduced into the world. Such at least is my view; but the full acceptance of this view must depend upon some very remote and very speculative considerations bearing upon the nature and purport of the whole existence and evolution of man. Yet however remote and speculative the thesis which I defend may be, it is not one whit remoter or more speculative than the view which, _faute de mieux_, is often tacitly assumed by scientific writers.