And having thus duly apologized, I will venture to transgress and digress anew, and mention here a kind of melodic malady, a singular obsession to which I am subject, and which I will call unconscious musical cerebration. I am never without some tune running in my head--never for a moment; not that I am always aware of it; existence would be insupportable if I were. What part of my brain sings it, or rather in what part of my brain it sings itself, I cannot imagine--probably in some useless corner full of cobwebs and lumber that is fit for nothing else. But it never leaves off; now it is one tune, now another; now a song _without_ words, now _with_; sometimes it is near the surface, so to speak, and I am vaguely conscious of it as I read or work, or talk or think; sometimes to make sure it is there I have to dive for it deep into myself, and I never fail to find it after a while, and bring it up to the top. It is the "Carnival of Venice," let us say; then I let it sink again, and it changes without my knowing; so that when I take another dive the "Carnival of Venice" has become "Il Mio Tesoro," or the "Marseillaise," or "Pretty Little Polly Perkins of Paddington Green." And Heaven knows what tunes, unheard and unperceived, this internal barrel-organ has been grinding meanwhile. Sometimes it intrudes itself so persistently as to become a nuisance, and the only way to get rid of it is to whistle or sing myself. For instance, I may be mentally reciting for my solace and delectation some beloved lyric like "The Waterfowl," or "Tears, Idle Tears," or "Break, Break, Break"; and all the while, between the lines, this fiend of a subcerebral vocalist, like a wandering minstrel in a distant square, insists on singing, "Cheer, Boys, Cheer," or, "Tommy, make room for your uncle" (tunes I cannot abide), with words, accompaniment, and all, complete, and not quite so refined an accent as I could wish; so that I have to leave off my recitation and whistle "J'ai du Bon Tabac" in quite a different key to exorcise it. But this, at least, I will say for this never still small voice of mine: its intonation is always perfect; it keeps ideal time, and its quality, though rather thin and somewhat nasal and quite peculiar, is not unsympathetic. Sometimes, indeed (as in that Islington omnibus), I can compel it to imitate, _a s'y meprendre_, the tones of some singer I have recently heard, and thus make for myself a ghostly music which is not to be despised. Occasionally, too, and quite unbidden, it would warble little impromptu inward melodies of my own composition, which often seemed to me extremely pretty, old-fashioned, and quaint; but one is not a fair judge of one's own productions, especially during the heat of inspiration; and I had not the means of recording them, as I had never learned the musical notes. What the world has lost! Now whose this small voice was I did not find out till many years later, _for it was not mine_!