ing the general form
of grains of wheat. Secure a portion of the mesentery over a circular
opening in a thin piece of cork and examine it with a microscope of low
power. Follow the course of the nerve fiber to the nerve from which it
branches.

*To show Relative Sensitiveness of Different Parts of the Skin.*--Holding a
bristle between the fingers, bring the end in contact with the skin,
noting the amount of pressure necessary to cause a sensation of touch.
Test the lips, tongue, tips of fingers, and palm and back of hand, trying
different sizes of bristles. Has the degree of sensitiveness any relation
to the thickness of the cuticle?

*To show Perceptive Differences of Different Portions of the Skin.*--Place
the points of a pair of dividers on the back of the hand of one who looks
in the opposite direction. Is one point felt or two? Repeat several times,
changing the distance between the points until it is fully determined how
near the two points must be placed in order to be felt as one. In like
manner test other parts of the body, as the tips of the fingers and the
back of the neck. Compare results obtained at different places.

*To locate Warm and Cold Sensation Spots.*--Slowly and evenly draw a
blunt-pointed piece of metal over the back of the neck. If it be of the
same temperature as the skin, only touch sensations will be experienced.
If it be a little colder (the temperature of the room) sensations of cold
will be felt at certain spots. If slightly warmer than the body, heat
sensation spots will be found on other parts of the skin. If the heat and
cold sensation spots be marked and tested from day to day they will be
found to remain constant as to position. Inference.

CHAPTER XXI - THE LARYNX AND THE EAR

Man is a social being. His inclinations are not to live alone, but to be a
part of that great human organization known as society. For men to work
together, to be mutually helpful one to another, requires the ability to
exchange ideas and this in turn requires some means of communication.(115)
One means of communication is found in certain movements of the
atmosphere, known as _sound waves_. In the exchange of ideas by this means
there are employed two of the most interesting divisions of the body--the
larynx and the ear. The first is an instrument for the production of sound
waves; the second is the sense organ which enables the sound waves to act
as stimuli to the nervous system.

*Nature of Sou