rection being only through a distance of 1/4
millimeter. (This subject was not so strongly motor as the preceding
one.) The reaction followed promptly as seen in curve 6. It was the
decided raising of the head which follows the head-jerk, that prevented
the usual back-step with the left foot, when the subject was working
with Hans.

[Illustration: FIG. 6.]

[Illustration: FIG. 7.]

Figure 8 (von Manteuffel) is typical of strong and at the same time
economical concentration. Respiration, normally deep and very regular,
is for a time completely inhibited. Tension rises steadily and the head
gradually inclines forward. In the interval between the number before
the final one and the final one the subject makes a sudden bend forward
and immediately upon reaching the final number gives a violent jerk of
the head, upward. The attention here would be characterized as being of
type III, described on page 94. (Owing to lack of space it is impossible
to give an example of type II, which is only to be found in the case of
very large numbers.)

Figure 9 (von Allesch) is expressive of great, but--according to the
subject's introspection--not economical concentration. Respiration,
which before and after the test was quite regular, during the test
itself shows a pause. (The tiny waves are due to the heart-beat.) The
subject had thought of 5, and this number is accompanied by a decided
head-jerk. But we note that even before the final jerk a number of less
pronounced jerks occur--the result of poorly regulated psychic tension.

[Illustration: FIG. 8.]

[Illustration: FIG. 9.]

Figure 10 (Schillings) depicts a very high degree of uneconomical
concentration. There was sudden concentration at the beginning of the
test, and a steady increase throughout its course. Accordingly Mr.
Schillings bent forward at the start, and inclined still farther
forward at the second--and just before the third--tap. But at 3 there is
a sudden upward jerk. The number thought of had been 4, tension
therefore had exploded, as it were, too soon.

[Illustration: FIG. 10.]

Figure 11 (again of Schillings) gives indications, on the other hand, of
a medium and economic concentration of attention, which is more normal
in character. The number thought of was 4.

[Illustration: FIG. 11.]

Figure 12 (Schillings again) is indicative of a low degree of psychic
tension. With the very first tap the head begins to rise and continues
to do so throughout the test