horse it sometimes happened that he had merely thought
of making a certain turn, when the horse immediately executed it,
before he, the rider, had to his knowledge given any sign or aid. An
observation belonging under this head is also made in Tolstoi's
"Anna Karenina"[67], this perfect mine of acute psychological
observation. In the famous description of the race we are told
concerning Count Wronskij riding his Frou-Frou just behind Machotin
mounted upon Gladiator, who was leading the race: "At the very
moment when Wronskij thought that it was time to overtake Machotin,
Frou-Frou, divining her master's thought, increased her pace
considerably and this without any incitement on his part. She began
to come nearer to Gladiator from the more favorable, the near side.
But Machotin would not give it up. Wronskij was just considering
that he might get past by making the larger circuit on the off-side,
when Frou-Frou was already changing direction and began to pass
Gladiator on that side." Similar experiences might be gathered
elsewhere. Not infrequently the reflection of the rider that his
horse had not for a long time indulged in some trick peculiar to
him, will immediately call it forth; or doubts on the part of the
rider concerning the possibility of crossing some barrier, are often
the cause of the horse's fall or of his refusal to leap and of his
running away.]

Let us turn now from the consideration of visual perception to that of
auditory perception in the horse. We saw that the fact that Hans was
able to respond to commands which were only inwardly enunciated, that
is, commands which were merely thought of but not spoken, was not proof
of great acuity of hearing, but rather that hearing was not at all
involved. If Hans had been deaf he would, none the less, have promptly
obeyed the commands. Blind and near-sighted horses try to overcome their
deficiency by means of the sense of hearing, and hence show a pronounced
play of ears. In the case of the Osten horse, however, attention has
been diverted from auditory stimuli in the process of habituation to
visual signs, and as a result ear-movements are almost completely
wanting. One is not of course permitted to deny _a priori_ that perhaps
some associations might have been formed between objects and the vocal
signs belonging to them, e. g., between the colored cloths and the names
of the co