actually isolated in the laboratory, and had been proved capable of reproducing the disease, that the connection of certain maladies with the presence of certain microbes in the body became, from a plausible hypothesis, an accepted conclusion of Science. So here it is important to bear in mind that dreams, visions, and apparitions, however captivating to the imagination, do not form the main argument for believing in some new mode of communication between human minds. If all the cases of the kind hitherto recorded could be shown one by one to be explicable by more familiar causes,--though the result would indeed be to add a remarkable chapter to the history of human error; though it would be a singular paradox that so many intelligent witnesses should have been so mistaken, and with such undesigned unanimity; and that a whole class of alleged phenomena should have sprung up without any substantial basis,--the grounds for the belief in telepathy would not be seriously affected; we should merely have to modify our conceptions of its nature, and restrict its boundaries. But in fact there is no reason to anticipate so lame a conclusion. The incidents, of which examples will be adduced in the succeeding chapters, though their value will be differently estimated by different minds, are yet in their aggregate not such as can plausibly be attributed to misrepresentation or chance coincidence. And, first, it is important to note that the cases must be considered in the aggregate. Separately, no doubt, each particular case is susceptible of more or less adequate explanation by some well-known cause; and in the last resort it would be unreasonable to stake the credit of any single witness, however eminent, against what Hume would call the uniform experience of mankind. But as a matter of fact the experience of mankind is not uniform in this matter; and when we are forced by the mere accumulation of testimony to go on adding one strained and improbable explanation to another, and to assume at last an epidemic of misrepresentation, perhaps even an organised conspiracy of falsehood, a point is at length reached in which the sum of improbabilities involved in the negation of thought-transference must outweigh the single improbability of a new mode of mental affection. If to any reader that point should seem not yet to have been reached--and the position could scarcely be held an unreasonable one--I would remind him that the cases quoted in this book form but a small part of the evidence so far accumulated; and I would ask that he should reserve his judgment until he has studied the whole of the evidence recorded in _Phantasms of the Living_, in the _Proceedings_ of the American Society for Psychical Research, the scattered cases appearing from time to time in the pages of various English and Continental periodicals dealing with this subject, and the ever-growing mass of testimony printed in the _Proceedings_ and