=Education.= Throughout the preceding chapters, we have emphasized the
educational importance of the facts discussed. There is little left to
say here except to summarize the main facts. Since education is a matter
of making a child over into what he ought to be, the science of
education demands a knowledge of the original nature of children. This
means that one must know the nature of instincts, their relations to one
another, their order of development, and the possibilities of their
being changed, modified, developed, suppressed. It means that one must
know the nature of the child's mind in all its various functions, the
development and significance of these functions,--memory, association,
imagination, and attention. The science especially demands that we
understand the principles of habit-formation, the laws of economical
learning, and the laws of memory.

This psychological knowledge must form the ground-work in the education
of teachers for their profession. In addition to this general
preparation of the teacher, psychology will render the schools a great
service through the psycho-clinicist, who will be a psychological expert
working under the superintendents of our school systems. His duty will
be to supervise the work of mental testing, the work of diagnosis for
feeble-mindedness and selection of the subnormal children, the teaching
of such children. He will give advice in all cases which demand expert
psychological knowledge.

=Medicine.= In the first place, there is a department of medicine which
deals with nervous diseases, such as insanity, double personality,
severe nervous shock, hallucination, etc. This entire aspect of medicine
is wholly psychological. But psychology can be of service to the general
practitioner both in the diagnosis and treatment of disease. A thorough
psychological knowledge of human nature will assist a physician in
diagnosis. Often the best way to find out what ails a patient's body is
through the patient's mind, and the doctor must know how to get the
truth from the patient's mind even in those cases in which the patient
is actually trying to conceal the truth. A profound practical knowledge
of human nature is necessary,--a knowledge which can be obtained only
by long and careful technical study as well as practice and experience.

Psychology can be of service in the treatment of disease. The physician
must understand the peculiar mental characteristics of his patient in
ord