As every creature is furnished with teeth to seize and eat, and with stomach to digest its food, so the memory is furnished with a perfect apparatus. There is no book like the memory, none with such a good index, and that of every kind, alphabetic, systematic, arranged by names of persons, by colors, tastes, smells, shapes, likeness, unlikeness, by all sorts of mysterious hooks and eyes to catch and hold, and contrivances for giving a hint. The memory collects and re-collects. We figure it as if the mind were a kind of looking-glass, which being carried through the street of time receives on its clear plate every image that passes; only with this difference that our plate is iodized so that every image sinks into it, and is held there. But in addition to this property it has one more, this, namely, that of all the million images that are imprinted, the very one we want reappears in the centre of the plate in the moment when we want it. We can tell much about it, but you must not ask us what it is. On seeing a face I am aware that I have seen it before, or that I have not seen it before. On hearing a fact told I am aware that I knew it already. You say the first words of the old song, and I finish the line and the stanza. But where I have them, or what becomes of them when I am not thinking of them for months and years, that they should lie so still, as if they did not exist, and yet so nigh that they come on the instant when they are called for, never any man was so sharp-sighted, or could turn himself inside out quick enough to find. ’Tis because of the believed incompatibility of the affirmative and advancing attitude of the mind with tenacious acts of recollection that people are often reproached with living in their memory. Late in life we live by memory, and in our solstices or periods of stagnation; as the starved camel in the desert lives on his humps. Memory was called by the schoolmen _vespertina cognitio_, evening knowledge, in distinction from the command of the future which we have by the knowledge of causes, and which they called _matutina cognitio_, or morning knowledge. Am I asked whether the thoughts clothe themselves in words? I answer, Yes, always; but they are apt to be instantly forgotten. Never was truer fable than that of the Sibyl’s writing on leaves which the wind scatters. The difference between men is that in one the memory with inconceivable swiftness flies after and re-collects the flying leaves,—flies on wing as fast as that mysterious whirlwind, and the envious Fate is baffled.