The Greeks made Mnemosyne the mother of the Muses, and for us, under a less poetical form, memory is the indispensable bond of union of the intellectual faculties.
The senses reveal to us the external world, the intellect apprehends the sensations, and rising from material notions to abstract conceptions, embraces all that man is permitted to learn or to know; but it is the memory which enables us to record, as in a book, facts and results, to compare and to judge, to express thought by language, and to share the thoughts of others. Without memory man would not recognize the ties of blood, of friendship, or of gratitude; the past would have no existence for him, his life would only embrace the present moment, and would flow on like the period immediately succeeding birth. Deprived of experience, impelled by blind instinct, isolated in creation, he could not exist with organs which render necessary everything of which he would be deprived. We cannot therefore imagine the human race without memory, and in order to find an organization without this faculty we must descend to the lowest grades of animal life.
Memory is of a compound nature: partaking of body and of spirit, it is a reflection, an image of ourselves, since it carries us back to every moment that has impressed our lives. An exact and enthusiastic historian of the facts which she recounts to us, she seems to add to our existence the hours already passed, but as she approaches epochs she rudely makes us sensible of the flight of time. It may be happiness that makes us recall hours of pleasure, or in misfortune we may remember them with that pain of which the poet sings. She shows us the faces of all who have had a part in our existence, sometimes an isolated portrait, and at others a crowded gallery; a minute object, a plant, a rock, or the grandest scenes in nature; a word, or the entire work of a writer; a fact, or the history of a people. She carries us back in an instant to the most vivid impressions, or to the most abstract conceptions, whether of the senses or the intellect In taking the form of sensation or of thought, she makes us traverse time and space with a swiftness of which nothing material can give us an idea; we might indeed say, that time and space have no existence for the memory, if she did not in surmounting them awaken the idea of the one and the other. Obeying the behests of the will, memory retraces a scientific doctrine as a whole and in detail, the nicest distinctions of the most violent dispute, the series of systems of philosophy, all, in a word, that science or the most profound erudition has been able to classify in the mind.
We find everywhere the records of extraordinary memories, great numbers of which come down to us from antiquity.
Mithridates spoke twenty-two languages or dialects according to Aulus Gellius, and forty according to Pliny. Scipio the Asiatic knew most of his legionaries by name; Julius Caesar, Hortensius, Lucullus, Adrian, and many others, prove that a powerful memory is not incompatible with a superior mind. Pic de la Mirandole was a fresh example in the fifteenth century, as were also Leibnitz and Haller in the eighteenth. The last-mentioned cites a German, named Muller, who spoke twenty languages, and in our day we have Cardinal Mezzofanti, who spoke nearly fifty, exclusive of dialects, conversing with the pupils of the College of the Propaganda, who had come from every quarter of the globe.
It is related also that Scaliger learned Homer by heart in twenty-one days, and the other Greek poets in four months; and we are assured that Magliabecchi could dictate whole books after having read them once; and if some of these examples of prodigious memory are not verified, they are at least rendered very probable by those which are incontestable.
It was an extraordinary memory which enabled the young Sicilian shepherd, Mangiamele, to calculate mentally with such rapidity, that the members of the Academy of Sciences could scarcely follow him even by the aid of the most,expeditious processes. But the very ordinary intellect of this young man proves that in his case memory was a faculty out of all proportion to the others, a circumstance often observed especially in children.
Memory is sometimes awakened by a sensation which carries us back to the time and place where such or a similar sensation was produced. This memory of the senses acts Upon us with extraordinary power, it is one of the most effective means which writers possess of touching the human heart Eneas wept on beholding a picture on the walls of Carthage, which recalled the misfortunes of his country. "En Priamus" Behold Priam! said he, addressing his companions in exile. Andromache watered with her tears the grassy mound she had consecrated to the memory of Hector on the banks of another Simois; and the Florentine accent of Dante made the Ghibeline Farinata forget the tortures of hell.
In former times the musicians of the Swiss troops in the service of France were forbidden, under severe penalties, to play their national airs, and especially the "Ranz des Vaches," as it caused the soldiers to desert, or made them home-sick. Taste and smell are not less powerful in awakening memory, even after many years have passed.
The seat of memory has been vainly sought in the brain. Gall and several other physiologists have placed it in the anterior lobes, and the phrenological school assigns certain circumscribed portions to the memory of words, of places, of numbers, and of persons, etc But this localization is not justified by observation, and it is no more required by the memory than by the other faculties. Indeed, the impossibility of attributing to the brain the projections which vary solely according to the dimensions of the frontal sinus, was one of the objections to the doctrine of Gall. It is remarkable, also, that contrary to the opinion of phrenologists, the greater or less prominence of the eye (that is, the greater or less depth of the orbit) bears no relation to the development of the memory. There is more foundation for the observation of particular aptitudes of memory, specially to retain words, facts, numbers, etc. We may go still further, if we observe the changes induced by disease, for in certain cases the memory fails to retain substantives, or verbs, or other classes of words only, while all others are retained without difficulty. We may therefore suppose that certain parts of the brain are devoted specially to each detail of the memory as to the other faculties, as to the sensation of every nervous filament which transmits a tactile impression from any point of the body. This almost infinitesimal division of the brain will not astonish us in view of analogous facts derived from observation, or which reason imposes upon us, although no material demonstration is possible; yet we must also admit that the brain, as an organ of apprehension, acts as a whole, and that if a distinct apparatus exists for the memory, its action is at once single and multiform, each of its parts receiving with equal aptitude the impression of the ideas which are assigned to it Is it not thus that the innumerable divisions of the retina perceive with equal distinctness degrees of light? and is it not rational to suppose that it is the same with the region of the brain, which receives the nervous filaments which spring from every portion of the retina?
Very feeble in the first stages of life, the memory is developed along with the cerebral convolutions, and the gray or cortical substance. It loses its facility as mature age succeeds to youth, and retains with more difficulty the facts confided to it in proportion as years accumulate. In the aged it retains the impressions acquired during the first half of life, though in some fortunately endowed organizations it continues to increase its stores. Cato learned Greek in his old age; and Baron Humboldt at fourscore embodied in his Cosmos the whole circle of the sciences, and their most recent discoveries.