In dealing with the long vista of prehistoric time, it is very difficult for us, in our effort after perspective, not to shorten unduly in our thoughts the vast epochs of its duration. We tend, too, to forget, that in these unnumbered millennia there was ample time for it to be possible over certain areas of Europe to evolve what were practically new races, through the prepotency of particular stocks and the annihilation of others. During these epochs, again, after speech had arisen, there was time enough to recast completely many a language, for before the dawn of history language was no more free from change than it is now, and in these immense epochs whatever ideas as to the world of their surroundings were vaguely felt by prehistoric men and formulated for them by their kinsmen of genius, had abundant time in which to die or to win supremacy. There must have been aeons before the dawn even of conscious animism, and the experiment of trying sympathetic magic was, when first attempted, probably regarded as a master-stroke of genius. The Stone Age itself was a long era of great if slow progress in civilisation, and the evolution of the practices and ideas which emerge as the concomitants of its agricultural stage, when closely regarded, bear testimony to the mind's capacity for religious progress in the light of experience and intelligent experiment, and at the same time to the errors into which it fell. The Stone Age has left its sediment in all the folk-lore of the world. To the casual observer many of the ideas embedded in it may seem a mass of error, and so they are when judged unhistorically, but when viewed critically, and at the same time historically, they afford many glimpses of prehistoric genius in a world where life was of necessity a great experiment. The folk-lore of the world reveals for the same stages of civilisation a wonderful uniformity and homogeneity, as Dr. J. G. Frazer has abundantly shown in his _Golden Bough_. This uniformity is not, however, due to necessary uniformity of origin, but to a great extent to the fact that it represents the state of equilibrium arrived at between minds at a certain level and their environment, along lines of thought directed by the momentum given by the traditions of millennia, and the survival in history of the men who carefully regarded them. The apparently unreasoned prohibitions often known as 'taboos,' many of which still persist even in modern civilised life, have their roots in ideas and experiences which no speculation of ours can now completely fathom, however much we may guess at their origin. Many of these ancient prohibitions have vanished under new conditions, others have often survived from a real or supposed harmony with new experiences, that have arisen in the course of man's history. After passing through a stage when he was too preoccupied with his material cares and wants to consider whether he was haunted or not, early man in the Celtic world as