in many independent quarters for nearly a generation; of recent years the baffling manifestations of dissociated personality are, especially in France and America, being made the subject of careful and prolonged research; and automatic reactions are being accurately measured in psychological laboratories. Now that this province has been definitely annexed by medical men and professional psychologists, the special function of the Society for Psychical Research is fulfilled. The investigation is not of course concluded; it is in fact little more than begun. Our own researches will continue, it is hoped, to yield fruit: they are indeed probably necessary for the elucidation of some aspects of the subject. But the study as a whole has reached a stage at which the wider resources of the alienist's clinique, and the more exact methods of the psychological laboratory are needed for its further progress. To enable the reader to appreciate the real bearing of the evidence presented in the two chapters which follow, it is necessary to give some account of the results already attained and of the conclusions to which they point, even though at the present stage of the nascent science a brief-summary of this kind must necessarily be incomplete and perhaps to some extent misleading.
Briefly then, to the older philosophy the mind of man seemed a thing apart, a clear-cut indissoluble unity, whose permanence and identity admitted neither doubt or degree. To the new experimental psychology, the unity of consciousness is a mere
