tion of the
heart, when lived over again in memory, are again accompanied by all
these bodily activities. Your memory of a hairbreadth escape will bring
to your cheek the pallor that marked it when the incident occurred.

The formation and existence of "complexes" explains the origin of many
functional diseases of the body--that is to say, diseases involving no
loss or destruction of tissue, but consisting simply in a failure on the
part of some bodily organ to perform its allotted function naturally and
effectively.

[Sidenote: _Automatically Working Mental Mechanisms_]

Thus, in hay fever or "rose cold" the tears, the inflammation of the
membranes of the nose, the cough, the other trying symptoms, all are
linked with the sight of a rose, or dust, or sunlight, or some other
outside fact to which attention has been called as the cause of hay
fever, into a complex, "an automatically working mechanism." And the
validity of this explanation of the regular recurrence of attacks of
this disease is sufficiently demonstrated by the fact that a paper rose
is likely to prove just as effective in producing all the symptoms of
the disease as a rose out of Nature's garden.

Another striking illustration of the working of this principle is
afforded by two gentlemen of my acquaintance, brothers, each of whom
since boyhood has had unfailing attacks of sneezing upon first arising
in the morning. No sooner is one of these men awake and seated upon the
edge of his bed for dressing than he begins to sneeze, and he continues
to sneeze for fifteen or twenty minutes thereafter, although he has no
"cold" and never sneezes at any other time.

[Sidenote: _Two Classes of "Complexes"_]

Obviously, if absolutely all mental experiences are preserved, they
consist altogether of two broad classes of complexes: first, those that
are momentarily _active in consciousness_, forming part of the present
mental picture, and, second, all the others--that is to say, all past
experiences that are _not at the present moment before the mind's eye_.

There are, then, _conscious_ complexes and _subconscious_ complexes,
complexes of _consciousness_ and complexes of _subconsciousness_.

[Sidenote: _The Subconscious Storehouse_]

And of the complexes of subconsciousness, some are far more readily
recalled than others. Some are forever popping into one's thoughts,
while others can be brought to the light of consciousness only by some
unusual and deep-probing