nt
had not been present at any of the experiments, was asked to put the
questions to the horse. Mr. von Osten went into the house, accompanied
by a member of the commission. And again, Mr. Schillings would go out
before the second part of the test, without having met Mr. von Osten.

Five tests were made in this way. They were not attended by such amazing
success as were the preceding ones, but nevertheless the results were
surprising. The horse nearly always repeated the number itself, instead
of performing the operation required. Since, however, Mr. Schillings,
owing to a misunderstanding, had, in the first two cases, said to the
horse: "You are to repeat this number for Mr. von Osten", the errors
might appear to be a result of this request.

At the final discussion, the result of which was the unanimous
declaration which was given for publication, not only the data obtained
during these two sessions, but also the earlier experiences of some of
the members of the commission were taken into consideration. None of the
tests witnessed could be referred to chance or to the use of tricks.
Count zu Castell pointed out that in the course of eight days he had
elicited forty correct responses from the horse, among them some in
regard to which he himself had been momentarily in error. Other members
recalled the many instances in previous exhibitions, during which both
Mr. Schillings and Mr. von Osten were absent, when questions were put to
the horse by others. The commission also had access to a detailed
account written by Professor Stumpf on Mr. von Osten's method of
instruction, based on the explanations and demonstrations which Mr. von
Osten had himself given. As a result of these considerations the
commission felt under obligations to give public expression to its
conviction. In the report it limited itself, however, to the purely
negative side--principally in denying the use of tricks,--and expressed
no opinion with regard to the actual genesis of the horse's
accomplishments, since it believed that there was great possibility that
other factors were involved which ought to be carefully investigated.

SUPPLEMENT IV

THE REPORT OF DECEMBER 9TH, 1904

Together with Dr. E. von Hornbostel and Mr. O. Pfungst, I have tried
during the past few weeks to find an explanation of the accomplishments
of the horse 'Hans' by the experimental method. We had access to the
horse in the absence of the master and groom. The results