ou may be apprehensive about bewildering and
confusing the memory, but not about overloading it, in the strict sense
of the word. The faculty for remembering is not diminished in proportion
to what one has learnt, just as little as the number of moulds in which
you cast sand, lessens its capacity for being cast in new moulds. In
this sense the memory is bottomless. And yet the greater and more
various any one's knowledge, the longer he takes to find out anything
that may suddenly be asked him; because he is like a shopkeeper who has
to get the article wanted from a large and multifarious store; or, more
strictly speaking, because out of many possible trains of thought he has
to recall exactly that one which, as a result of previous training,
leads to the matter in question. For the memory is not a repository of
things you wish to preserve, but a mere dexterity of the intellectual
powers; hence the mind always contains its sum of knowledge only
potentially, never actually.

It sometimes happens that my memory will not reproduce some word in a
foreign language, or a name, or some artistic expression, although I
know it very well. After I have bothered myself in vain about it for a
longer or a shorter time, I give up thinking about it altogether. An
hour or two afterwards, in rare cases even later still, sometimes only
after four or five weeks, the word I was trying to recall occurs to me
while I am thinking of something else, as suddenly as if some one had
whispered it to me. After noticing this phenomenon with wonder for very
many years, I have come to think that the probable explanation of it is
as follows. After the troublesome and unsuccessful search, my will
retains its craving to know the word, and so sets a watch for it in the
intellect. Later on, in the course and play of thought, some word by
chance occurs having the same initial letters or some other resemblance
to the word which is sought; then the sentinel springs forward and
supplies what is wanting to make up the word, seizes it, and suddenly
brings it up in triumph, without my knowing where and how he got it; so
it seems as if some one had whispered it to me. It is the same process
as that adopted by a teacher towards a child who cannot repeat a word;
the teacher just suggests the first letter of the word, or even the
second too; then the child remembers it. In default of this process, you
can end by going methodically through all the letters of the alphabet