ich is
essentially different from ordinary "training" and is copied
from the system of instruction employed in primary schools. In
the opinion of the undersigned, the collective results of these
observations show that even unintentional signs of the kind at
present known were excluded. It is their unanimous opinion that
we have here to deal with a case that differs in principle from
all former and apparently similar cases; that it has nothing to
do with "training" in the accepted sense of the word, and that
it is consequently deserving of earnest and searching
scientific investigation. Berlin, September 12, 1904. [Here
follow the signatures, among which is that of Privy Councilor
Dr. C. Stumpf, university professor, director of the
Psychological Institute, member of the Berlin Academy of
Sciences.]

Anyone who has done critical work in the domain of hypnotism after the
manner insisted on by the Nancy school cannot help considering Stumpf's
method of investigation erroneous from the very outset. A first source
of error that had to be considered was that someone present--it
might have been Herr v. Osten or it might have been anyone
else--unintentionally had given the horse a sign when to stop tapping.
It cannot be considered sufficient, as stated in Stumpf's report, that
Herr v. Osten did not know the answer; no one should be present who
knows it. This is the first condition to be fulfilled when making such
experiments. Anybody who has been engaged in training hypnotized
subjects knows that these insignificant signs constitute one of the
chief sources of error. Some of the leading modern investigators in the
domain of hypnotism--Charcot and Heidenhain, for instance--were misled
by them at the time they thought they had discovered new physical
reflexes in hypnosis. But in 1904, by which time suggestion had been
sufficiently investigated to prevent such an occurrence, a psychologist
should not have fallen into an error that had been sufficiently made
more than twenty years previously. But the main point is this: signs
that are imperceptible to others are nevertheless perceived by a subject
trained to do so, no matter whether that subject be a human being or an
animal.

3. Social Suggestion and Mass or "Corporate" Action[153]

In most cases the crowd naturally is under leaders, who, with an
instinctive consciousness of the importance and strength of