Had a man of lesser renown and mental calibre than Mr. Wallace thrown the weight of his testimony into the scales in favour of spiritualism, there would have been neither necessity nor excuse for this digression. But both these pleas prevail when we find the co-formulator of the Darwinian theory among mediums and their dupes. The respectful attention which his words command: the tremendous claims which he makes on behalf of the phenomena at _séances_ as proving the existence of soul apart from body after death, and as revealing the conditions under which it lives, have made incumbent the foregoing attempt to indicate what other explanation is given of those phenomena, showing how these fall in with all we know of man's tendencies to imperfect observation and self-deception, and with all that history tells of the persistence of animistic ideas. A salutary lesson on the use and misuse of the imagination is thus taught. That which, under wholesome restraint, is the initiative and incentive of inquiry, of enterprise, and of noble ideas; unrestricted, leads the dreamer and the enthusiast into ingulfing quicksands of illusions and delusions. Hence the necessity of curbing a faculty so that in unison with reason, it works toward definite ends within the domain, marking man's limits of service. As Dr. Maudsley reminds us in his sane and sober book on Natural Causes and Supernatural Seeming, "not by standing out of Nature in the ecstasy of a rapt and over-strained idealism of any sort, but by large and close and faithful converse with Nature and human nature in all their moods, aspects, and relations, is the solid basis of fruitful ideas and the soundest mental development laid. The endeavour to stimulate and strain any mental function to an activity beyond the reach and need of a physical correlate in external nature, and to give it an independent value, is certainly an endeavour to go directly contrary to the sober and salutary method by which solid human development has taken place in the past, and is taking place in the present." * * * * * The story of Darwin's work must now be resumed. Shortly after the Linnæan meeting, he prepared a series of chapters which, always regarded by him as an "Abstract," ultimately took book form, and was published, under the title of the Origin of Species, on the 24th of November, 1859.