lors if both had been presented together oftener than was the
case.

But there is a dearth of reliable observation as to how far auditory
associations of this sort may be established in horses. Usually the
following is cited. Horses learn to start off, to stop, and to turn
about in response to calls. They are able to distinguish properly
between the expressions "right" and "left", or equivalent terms. Upon
command they will start to walk, to trot or to run. And they also know
the name by which they are usually called. All authors agree that
cavalry horses understand the common military commands; one writer even
avers that they excel the recruits in this respect.[69] Some believe
that in riding schools the horses pay closer heed to the calls of the
riding-master than to the control of unpractised riders, even when the
two are at variance with one another.[70] My experience with the Osten
horse and a number of other pertinent observations aroused in me the
suspicion that much that is called or spoken in the process of managing
a horse may possibly be just so much labor lost. In consequence I made a
series of relevant experiments. I have thus far tested twenty-five
horses of different kinds, from the imported Arabian and English
full-blood, down to the heavy draft-horse. The experiments were made
partly in the courtyard of military barracks, partly in the circus, and
partly in a riding-school or in private stalls. I am specially indebted
for kind assistance to Messrs. von Lucanus, Busch, and to H. H.
Burkhardt-Foottit and E. Schumann, the two excellent trainers connected
with the Busch Circus. During these tests, the horses were always amid
circumstances familiar to them, whether free or bridled, under a rider
or hitched to a wagon. All aids or signals, except the calls, were
eliminated in so far as it was possible.

The results of those tests were in substance as follows: Many horses
react to a smack of the lips by a rather fast trot. Many stop on the cry
"Hola" or "Brr". This last was nicely illustrated in the case of two
carriage horses supplied with large blinders and held with a loose rein,
and hitched to a landau. One of them regularly stopped when the "brr"
was given by the driver, whereas the other, which had not been
habituated to this signal, kept serenely on the trot, so that the
vehicle regularly veered off the track--a sure sign that no
unintentional aid was being given by means of the reins. Other horses,
a