In every idea emanating from genius, or even in every serious human idea -- born in the human brain -- there always remains something -- some sediment -- which cannot be expressed to others, though one wrote volumes and lectured upon it for five-and-thirty years. There is always a something, a remnant, which will never come out from your brain, but will remain there with you, and you alone, for ever and ever, and you will die, perhaps, without having imparted what may be the very essence of your idea to a single living soul.