Sometimes it happens that the most insane thought, the most impossible conception, will become so fixed in one's head that at length one believes the thought or the conception to be reality. Moreover, if with the thought or the conception there is combined a strong, a passionate, desire, one will come to look upon the said thought or conception as something fated, inevitable, and foreordained—something bound to happen. Whether by this there is connoted something in the nature of a combination of presentiments, or a great effort of will, or a self-annulment of one's true expectations, and so on, I do not know;