not yet been
perfected. When this was finally done, Mr. Schillings, who acted as
subject in those tests, had to be eliminated from the ranks of
appropriate subjects on account of the increasing inhibitions, which
gradually developed as described on page 120.

Analysis of such curves is rather difficult, and those of different
subjects cannot be directly compared. It is necessary to make a study of
the normal curve of each subject taken when his affective state could be
described as "indifferent". The influences of the purely physiological
processes, such as pulse[R] and respiration, must also be determined.
And even so, an interpretation of the curve becomes possible only when a
large mass of material is at hand, and when the introspections of the
subject are taken into consideration. The following remarks, therefore,
are not based solely upon the illustrations given, but upon the mass
total of my results.

[Footnote R: Slight head movements accompanying the pulse-beat were
until recently regarded as the symptom of certain diseases of the
vascular system (the so-called symptom of Nusset), but H. Frenkel
has now shown them to exist also in normal individuals.[19] I myself
discovered such movements (lateral as well as sagittal) more or less
pronounced in all the curves obtained from my subjects. The most
striking case was that of a young physician whose circulatory system
was perfectly healthy. In most instances I was able to note these
oscillatory movements directly and to count them without much
difficulty. For purposes of control the radial pulse was always
determined at the same time. The observation of the phenomenon
appears to be especially easy in the case of somewhat full-blooded
individuals.]

In beginning our analysis, let us take first the breathing curve. Our
results here were quite in accord with the view taken by Zoneff and
Meumann,[20] who believe that in the respiration is to be found a good
index of the affective tone of the subject's mental state. In the
greater number of cases it was possible to conclude as to the degree of
concentration of attention,--and when this was very great, it was even
possible to get a clue as to the number thought of. Since the high
degree of tension, under which a subject labored during a test, would be
accompanied by strong affective coloring, we cannot regard as normal any
of the curves here reproduced (with the excepti