Somnambulism and the conditions allied to it have always attracted peculiar interest, probably because most men have felt that common sleep, although so familiar, is yet a wondrous and solemn thing, and full of mysterious possibilities for each of us. Cases of somnambulism have naturally lost nothing when reported, the observer and the recorder being alike liable to enhance rather than lessen the mystery. The wholesome scepticism which now prevails as to the truly involuntary character of many nervous disorders was formerly less common. We know that some patients will subject themselves to constant suffering and discomfort, or will practise the most patient and painful imposture, for no conceivable object save to be exceptional or to attract attention; and there is no want of charity in suspecting that in some cases the somnambulism was but hysterical simulation or morbid malingering.