rred to a dog trained for the vaudeville-stage,
the gentleman concludes that, "our intelligent horse, as well as the
dog, is simply of fine nervous organization and hence highly susceptible
to suggestions".

What was to be done, with this mass of conflicting explanations?
Everyone considered his own opinion the only correct one, without,
however, being able to convince anyone else. The need here was not
simple affirmation, but proof.

CHAPTER II

EXPERIMENTS AND OBSERVATIONS

A. EXPERIMENTAL CONDITIONS

The observations on the horse under ordinary conditions would have been
quite insufficient for arriving at a decision as to the tenability of
the several possible explanations. For this purpose experimentation with
controlled conditions was necessary.

It was necessary, first, that the place in which the experiments were
performed should be guarded against sources of error and interruptions.
Several difficulties stood in the way of the removal of the horse to a
more convenient place. Therefore, a large canvas tent was erected within
the courtyard of Mr. von Osten. This afforded the necessary isolation
without hindering the free movements of the horse. After the essential
part of the experiment had been completed and the problem had been
practically solved, experimentation was sometimes conducted in the open
courtyard. A number of the experiments were also performed in the
horse's stall.

The choice of proper persons to experiment with the horse required
careful consideration. In so far as observations were to be made upon
the questioner, Mr. von Osten was of course indispensable. But to
obviate every objection he, as well as Mr. Schillings, had to be
excluded from the greater part of the experiments, and other persons
had to be selected who could learn to handle the horse. Now one would
have thought that the horse would respond to any moderately efficient
examiner. But as a matter of fact it was found that the horse would not
react at all in the case of the greater number of persons. Again, in the
case of others he would respond once or twice, but would then cease. All
told, Hans responded more or less readily to forty persons, but it was
only when he worked with Mr. von Osten or with Mr. Schillings, that his
responses were at all dependable. For this reason I undertook to
befriend the horse, and by happy chance it came to pass in a short time
he responded as readily to my questions as to those of the tw