charm, the mineral waters, the shrine, and in the good God, has
brought health to many thousands of sufferers. People have always
reckoned on this bodily result from a mental state. They have
intuitively known better than to tell a sick person that he is looking
worse, but they have not always known why. They have known that a fit
of anger is apt to bring on a headache, but they have not stopped to
look for the reason, or if they have, they have often gotten
themselves into a tangle. This is because there has always been, until
recently, a missing link. Now the link has been found. After the last
chapter, it will not be hard to understand that this connecting link,
this go-between of body and mind, is nothing else than the
subconscious mind. When we remember that it has the double power of
knowing our thoughts and of controlling our bodies, it is not hard to
see how an idea can translate itself into a pain, nor to realize with
new vividness the truth of the statement that healthy mental states
make for health, and unhealthy mental states for illness.

=Suggestion and Emotion.= There are still many gaps in our knowledge
of the ways of the subconscious, but investigation has thrown a good
deal of light on the problem. Two of the principles already discussed
are sufficient to explain most of the phenomena. These are, first,
that the subconscious is amenable to control by suggestion, and
secondly, that it is greatly influenced by emotion. Tracing back the
principles behind any example of the power of mind over body, one
finds at the root of the matter either a suggestion or an emotion, or
both. If, then, the stimulating and depressing effects of mental
states are to be understood, the first Step must be a fuller
understanding of the laws governing suggestion and emotion.