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.
CHAPTER X. WHAT WE SHOULD EXPECT TO FIND IF DIFFERENTIATIONS OF STRUCTURE AND INSTINCT ARE MAINLY DUE TO MEMORY.
TO repeat briefly;—we remember best our last few performances of any given kind, and our present performance is most likely to resemble one or other of these; we only remember our earlier performances by way of residuum; nevertheless, at times, some older feature is liable to reappear.
We take our steps in the same order on each successive occasion, and are for the most part incapable of changing that order.
The introduction of slightly new elements into our manner is attended with benefit; the new can be fused with the old, and the monotony of our action is relieved. But if the new element is too foreign, we cannot fuse the old and new—nature seeming equally to hate too wide a deviation from our ordinary practice, and no deviation at all. Or, in plain English—if any one gives us a new idea which is not too far ahead of us, such an idea is often of great service to us, and may give new life to our work—in fact, we soon go back, unless we more or less frequently come into contact with new ideas, and are capable of understanding and making use of them; if; on the other hand, they are too new, and too little led up to, so that we find them too strange and hard to be able to understand them and adopt them, then they put us out, with every degree of completeness—from simply causing us to fail in this or that particular part, to rendering us incapable of even trying to do our work at all, from pure despair of succeeding.