My friends have so often asked me this question, that I think, before I close this book, I am justified in answering it, at all events, as far as I myself am concerned. How often have I sat, surrounded by an interested audience, who knew me too well to think me either a lunatic or a liar; and after I have told them some of the most marvellous and thrilling of my experiences, they have assailed me with these questions, "But what _is_ it? And what _good_ does it do? _What is it?_" There, my friends, I confess you stagger me! I can no more tell you what it is than I can tell you what _you_ are or what _I_ am. We know that, like Topsy, we "grew." We know that, given certain conditions and favorable accessories, a child comes into this world, and a seed sprouts through the dark earth and becomes a flower; but though we know the cause and see the effect, the greatest man of science, or the greatest botanist, cannot tell you how the child is made, nor how the plant grows. Neither can I (or any one) tell you _what_ the power is that enables a spirit to make itself apparent. I can only say that it can do so, and refer you to the Creator of you and me and the entire universe. The commonest things the earth produces are all miracles, from the growing of a mustard seed to the expansion of a human brain. What is more wonderful than the hatching of an egg? You see it done every day. It has become so common that you regard it as an event of no consequence. You know the exact number of days the bird must sit to produce a live chicken with all its functions ready for nature's use, but you see nothing wonderful in it. All birds can do the same, and you would not waste your time in speculating on the wondrous effect of heat upon a liquid substance which turns to bone and blood and flesh and feathers.