We might very naturally suppose from the fact of the horse’s applying
his nose to everything new to him, that he always does so for the
purpose of smelling these objects; but I believe that it is as much or
more for the purpose of feeling, and that he makes use of his nose, or
muzzle, (as it is sometimes called), as we would of our hands; because
it is the only organ by which he can touch or feel anything with much
susceptibility.
I believe that he invariably makes use of the four senses--seeing,
hearing, smelling, and feeling--in all of his examinations, of which the
sense of feeling is, perhaps, the most important. And I think that, in
the experiment with the robe, his gradual approach and final touch with
his nose was as much for the purpose of feeling as anything else, his
sense of smell being so keen that it would not be necessary for him to
touch his nose against anything in order to get the proper scent; for it
is said that a horse can smell a man at the distance of a mile. And if
the scent of the robe was all that was necessary, he could get that
several rods off. But we know from experience, that if a horse sees and
smells a robe a short distance from him, he is very much frightened
(unless he is used to it) until he touches or feels it with his nose;
which is a positive proof that feeling is the controlling sense in this
case.