"There are all things preserved distinctly and under general heads, each having enetered by its own avenue, as light, and all colors and forms of bodies, by the eyes; by the ears all sorts of sounds; all smells by the avenue of the nostrils; all tastes by the mouth; and by the sensation of the whole body, what is hard or soft, hot or cold, smooth or rugged, heavy or light, either outwardly or inwardly to the body. All these doth that great harbor of the memory receive in her numberless secret and inexpressible windings, to be forthcoming, and brought out at need; each entering in by his own gate, and there laid up. Nor yet do the things themselves enter in; only the images of the things perceived, are there in readiness, for thought to recall. Which images, how they are formed, who can tell, though it doth plainly appear by which each hath been brought in and stored up? For even while I dwell in darkness and silence, in my memory I can produce colors, if I will, and discern betwixt black and white, and what others I will. Nor yet do sounds break in and disturb the image drawn in by my eyes which I am reviewing, though they also are there, lying dormant, and laid up, as it were, apart. For these too I call for, and forthwith they appear."
From the 1976 Translation version of "The Confessions of St. Augustine" (398 A.D.), Book 10, by Edward B. Pusey.
I've not found a more poetic description of the introspective function of memory, which is of course as relevant now as it was when written in the 4th century A.D.