This holds good concerning all actions which we do habitually, whether they involve laborious acquirement or not. Thus, if we have varied our usual dinner in some way that leaves a favourable impression upon our minds, so that our dinner may, in the language of the horticulturist, be said to have “sported,” our tendency will be to revert to this particular dinner either next day, or as soon as circumstances will allow, but it is possible that several hundred dinners may elapse before we can do so successfully, or before our memory reverts to this particular dinner.
4. As regards our habitual actions, however unconsciously we remember them, we, nevertheless, remember them with far greater intensity than many individual impressions or actions, it may be of much greater moment, that have happened to us more recently. Thus, many a man who has familiarised himself, for example, with the odes of Horace, so as to have had them at his fingers’ ends as the result of many repetitions, will be able years hence to repeat a given ode, though unable to remember any circumstance in connection with his having learnt it, and no less unable to remember when he repeated it last. A host of individual circumstances, many of them not unimportant, will have dropped out of his mind, along with a mass of literature read but once or twice, and not impressed upon the memory by several repetitions; but he returns to the well-known ode with so little effort, that he would not know that he was remembering unless his reason told him so. The ode seems more like something born with him.
We observe, also, that people who have become imbecile, or whose memory is much impaired, yet frequently retain their power of recalling impression which have been long ago repeatedly made upon them.
In such cases, people are sometimes seen to forget what happened last week, yesterday, or an hour ago, without even the smallest power of recovering their recollection; but the oft repeated earlier impression remains, though there may be no memory whatever of how it came to be impressed so deeply. The phenomena of memory, therefore, are exactly like those of consciousness and volition, in so far as that the consciousness of recollection vanishes, when the power of recollection has become intense. When we are aware that we are recollecting, and are trying, perhaps hard, to recollect, it is a sign that we do not recollect utterly. When we remember utterly and intensely, there is no conscious effort of recollection; our recollection can only be recognised by ourselves and others, through our performance itself, which testifies to the existence of a memory, that we could not otherwise follow or detect.
5. When circumstances have led us to change our habits of life—as when the university has succeeded school, or professional life the university—we get into many fresh ways, and leave many old ones. But on revisiting the old scene, unless the lapse of time has been inordinately great, we experience a desire to revert to old habits. We say that old associations crowd upon us. Let a Trinity man, after thirty years absence from Cambridge, pace for five minutes in the cloister of Neville’s Court, and listen to the echo of his footfall, as it licks up against the end of the cloister, or let an old Johnian stand wherever he likes in the third Court of St. John’s, in either case he will find the thirty years drop out of his life, as if they were half-an-hour; his life will have rolled back upon itself, to the date when he was an undergraduate, and his instinct will be to do almost mechanically, whatever it would have come most natural to him to do, when he was last there at the same season of the year, and the same hour of the day; and it is plain this is due to similarity of environment, for if the place he revisits be much changed, there will be little or no association.
So those who are accustomed at intervals to cross the Atlantic, get into certain habits on board ship, different to their usual ones. It may be that at home they never play whist; on board ship they do nothing else all the evening. At home they never touch spirits; on the voyage they regularly take a glass of something before they go to bed. They do not smoke at home; here they are smoking all day. Once the voyage is at an end, they return without an effort to their usual habits, and do not feel any wish for cards, spirits, or tobacco. They do not remember yesterday, when they did want all these things; at least, not with such force as to be influenced by it in their desires and actions; their true memory—the memory which makes them want, and do, reverts to the last occasion on which they were in circumstances like their present; they therefore want now what they wanted then, and nothing more; but when the time comes for them to go on shipboard again, no sooner do they smell the smell of the ship, than their real memory reverts to the times when they were last at sea, and striking a balance of their recollections, they smoke, play cards, and drink whisky and water.
We observe it then as a matter of the commonest daily occurrence within our own experience, that memory does fade completely away, and recur with the recurrence of surroundings like those which made any particular impression in the first instance. We observe that there is hardly any limit to the completeness and the length of time during which our memory may remain in abeyance. A smell may remind an old man of eighty of some incident of his childhood, forgotten for nearly as many years as he has lived. In other words, we observe that when an impression has been repeatedly made in a certain sequence on any living organism—that impression not having been prejudicial to the creature itself—the organism will have a tendency, on reassuming the shape and conditions in which it was when the impression was last made, to remember the impression, and therefore to do again now what it did then; all intermediate memories dropping clean out of mind, so far as they have any effect upon action.
6. Finally, we should note the suddenness and apparent caprice with which memory will assert itself at odd times; we have been saying or doing this or that, when suddenly a memory of something which happened to us, perhaps in infancy, comes into our head; nor can we in the least connect this recollection with the subject of which we have just been thinking, though doubtless there has been a connection, too rapid and subtle for our apprehension.
The foregoing phenomena of memory, so far as we can judge, would appear to be present themselves throughout the animal and vegetable kingdoms. This will be readily admitted as regards animals; as regards plants it may be inferred from the fact that they generally go on doing what they have been doing most lately, though accustomed to make certain changes at certain points in their existence. When the time comes for these changes, they appear to know it, and either bud forth into leaf or shed their leaves, as the case may be. If we keep a bulb in a paper bag it seems to remember having been a bulb before, until the time comes for it to put forth roots and grow. Then, if we supply it with earth and moisture, it seems to know where it is, and to go on doing now whatever it did when it was last planted; but if we keep it in the bag too long, it knows that it ought, according to its last experience, to be treated differently, and shows plain symptoms of uneasiness; it is distracted by the bag, which makes it remember its bulbhood, and also by the want of earth and water, without which associations its memory of its previous growth cannot be duly kindled. Its roots, therefore, which are most accustomed to earth and water, do not grow; but its leaves, which do not require contact with these things to jog their memory, make a more decided effort at development—a fact which would seem to go strongly in favour of the functional independence of the parts of all but the very simplest living organisms, if, indeed, more evidence were wanted in support of this.