CHAPTER III. MEMORY AND HABIT

There are two qualities of nervous tissues (possibly of all
living tissue) that are basic in all nervous and mental
processes. They are dependent upon the modificability of nerve
cells and fibers by stimuli, e. g., a light flashing through the
pupil and passing along the optical tracts to the occipital
cortex produces changes which constitute the basis of visual
memory. Experience modifies nervous tissue in definite manner,
and SOMETHING remembers. Who remembers? Who is conscious? Believe
what you please about that, call it ego, soul, call it
consciousness dipped out of a cosmic consciousness; and I have no
quarrel with you.

Memory has its mechanics, in the association of ideas, which
preoccupied the early English psychologists and philosophers; it
is the basis of thought and also of action, and it is a prime
mystery. We know its pathology, we think that memories for speech
have loci in the brain, the so-called motor memories in Broca's
area.[1] We know that a hemorrhage in these areas or in the
fibers passing from them, or a tumor pressing on them may destroy
or temporarily abolish these memories, so that a man may KNOW
what he wishes to say, understand speech and be unable to say it,
though he may write it (motor aphasia). In sensory aphasia the
defect is a loss of the capacity to understand spoken speech,
though the patient may be able to say what he himself wishes. (It
is fair to say that the definite location of these capacities in
definite areas has been challenged by Marie, Moutier and others,