e from reading, farsightedness is
indicated. If the subject cannot read up to the twenty-foot line,
nearsightedness or astigmatism is indicated.

12. _Hearing._ By consultation with the teacher of physics, plan an
experiment to show that the pitch of tones depends on vibration
frequency. Such an experiment can be very simply performed by rotating a
wheel having spokes. Hold a light stick against the spokes so that it
strikes each spoke. If the wheel is rotated so as to give twenty or
thirty strokes a second, a very low tone will be heard. By rotating the
wheel faster you get a higher tone. Other similar experiments can be
performed.

13. Acuity of hearing can be tested by finding the distance at which the
various members of the class can hear a watch-tick. The teacher can plan
an experiment using whispering instead of the watch-tick. (See the
author's _Examination of School Children_.)

14. By using the point of a nail, one can find the "cold spots" on the
skin. Warm the nail to about 40 degrees Centigrade and you can find the
"warm spots."

15. By touching the hairs on the back of the hand, you can stimulate the
"pressure spots."

16. By pricking the skin with the point of a needle, you can stimulate
the "pain spots."

17. The sense of taste is sensitive only to solutions that are sweet,
sour, salt, or bitter. Plan experiments to verify this point. What we
call the "taste" of many things is due chiefly to odor. Therefore in
experiments with taste, the nostrils should be stopped up with cotton.
It will be found, for example, that quinine and coffee are
indistinguishable if their odors be eliminated by stopping the nose. The
student should compare the taste of many substances put into the mouth
with the nostrils open with the taste of the same substances with the
nostrils closed.

REFERENCES FOR CLASS READING

COLVIN AND BAGLEY: _Human Behavior_, Chapters VII and XII.

MUeNSTERBERG: _Psychology, General and Applied_, Chapters III, IV, VI,
and VII.

PILLSBURY: _Essentials of Psychology_, Chapters II, III, and IV.

PYLE: _The Outlines of Educational Psychology_, Chapter II.

TITCHENER: _A Beginner's Psychology_, Chapter I, par. 3; also
Chapter II.

CHAPTER IV

INHERITED TENDENCIES

=Stimulus and Response.= We have learned something about the sense organs
and their functions. We have seen that it is through the sense organs
that the world affects us, stimulates us. And we have said that we are