It is certainly much better to have the textbook before one than to
teach the lesson after a disconnected and haphazard fashion from lack
of familiarity with its points. An excellent substitute for the text,
however, is an outline, or plan of the lesson embodying the main
points, illustrations, and applications to be made. Such an outline
will save the teacher from wandering too far afield in the
discussions, will insure unity in the lesson, and make certain that
important points shall not be overlooked.

A desirable rule for the teacher to set for himself would be so to
prepare for the recitation by mastery of the subject, and by lesson
plan or outline, _that he does not need to have the textbook open
before him when the pupils do not also have their books open_. The
teacher who will heroically meet this standard will soon find growing
in himself a feeling of mastery of his subjects and of joy in his
teaching.

4. _The principle of unity or continuity in questions_

Questions should be so planned that they develop or bring out the
unity of the lesson. It is possible for questions to be so haphazard
and disconnected that the pupil receives the impression of a series of
unrelated facts, rather than a unified and related subject. In good
questioning, one question naturally grows out of another, so that the
series develops step by step the truth contained in the lesson, and
brings it to the mind of the child as a complete whole.

This means that the teacher must know the whole subject so thoroughly
that the right questions come to him easily and naturally, and in the
right order to bring out the successive steps of the lesson in their
logical relations.

The difference between a related series of questions and an unrelated
is shown in two lists which follow. Both deal with the same
subject-matter, a physiology lesson on respiration. The questions of
the first list are not themselves faulty, but there is no continuity
among them; one does not grow out of another so as to "develop" the
subject in the minds of the class.

What change takes place in the air while in the lungs?

What change takes place in the blood while in the lungs?

How many cubic inches of air will the lungs contain?

How much of this cannot be expelled by breathing out?

How many times do we naturally breathe in a minute?

What are some of the effects of breathing impure air?

How is the oxygen carried by