autacoid is probably secreted by the so-called islands of Langer-
hans which are scattered throughout the pancreas).

Concluding Statements on the Glands and Muscles. --In the
present chapter, as in the preceding one, we have been dealing with
parts of the organism and their functioning. It remains to call
attention to the fact that only rarely do the various parts func-
tion in an isolated way. Any stimulation strong enough to reach
the motor side of the central nervous system brings about not
only narrow reflex and associated activities (segmental reactions)
but widespread changes in the organism as a whole. Even so
simple an activity as putting on our clothes and lacing up our
shoes in the morning involves a most complex series of adjust-
ments of a motor and glandular kind such as the proper relations
of action between extension and flexion, changes in autonomic
activity such as are seen in the regulation of the pupil and in
respiration and circulation. Our study of the glands has taught
us that muscular activity cannot go on for any length of time
without involving changes in those organs; sweat begins to form,
sugar is released to serve as, food for the muscles, adrenin is con-
tributed to the blood stream, which not only neutralizes fatigue
products but also acts upon the autonamic system in such a way
as to increase the flow of blood to the muscular organs in opera-
tion. The thyroid glands secrete and affect not only other glands,
either increasing their output or checking it, but also possibly
all of the cells of the body as well. The eating of the simplest
meal starts another widespread series of changes in the body
as a whole, beginning the moment food enters the mouth and
continuing until the products of digestion are absorbed and
stored for future use and the waste products eliminated.

The material we have gathered in the last three chapters
should emphasize the difference between physiology and psy-
chology. The science of physiology, deals with part reactions
such as we have been studying, whereas psychology deals with
the adjustments of the organism as a whole. We have entered
into these physiological studies in order to get a better grasp upon
what is meant by the whole organism. Our remaining studies
will deal almost exclusively with activities which require the
coöperation of the body as a whole.

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