pounds for each; but he offered to give double the price if he
might keep three or four of them for a few days in order to select one.
When asked how he could possibly learn so soon whether a particular
monkey would turn out a good actor, he answered that it all depended on
their power of attention. If when he was talking and explaining anything
to a monkey its attention was easily distracted, as by a fly on the
wall or other trifling object, the case was hopeless. If he tried by
punishment to make an inattentive monkey act, it turned sulky. On the
other hand, a monkey which carefully attended to him could always be
trained.

It is almost superfluous to state that animals have excellent _memories_
for persons and places. A baboon at the Cape of Good Hope, as I have
been informed by Sir Andrew Smith, recognised him with joy after an
absence of nine months. I had a dog who was savage and averse to all
strangers, and I purposely tried his memory after an absence of five
years and two days. I went near the stable where he lived and shouted to
him in my old manner; he showed no joy, but instantly followed me out
walking, and obeyed me exactly as if I had parted with him only half an
hour before. A train of old associations, dormant during five years, had
thus been instantaneously awakened in his mind. Even ants, as P. Huber
has clearly shown, recognised their fellow-ants belonging to the same
community after a separation of four months. Animals can certainly by
some means judge of the intervals of time between recurrent events.

The _Imagination_ is one of the highest prerogatives of man. By this
faculty he may unite former images and ideas, independently of the will,
and thus create brilliant and novel results. A poet, as Jean Paul
Richter remarks, "who must reflect whether he shall make a character say
yes or no--to the devil with him; he is only a stupid corpse." The value
of the products of our imagination depends of course on the number,
accuracy, and clearness of our impressions, on our judgment and taste in
selecting or rejecting the involuntary combinations, and to a certain
extent on our power of voluntarily combining them. As dogs, cats,
horses, and probably all the higher animals, even birds, have vivid
dreams, and this is shown by their movements and the sounds uttered, we
must admit that they possess some power of imagination. There must be
something special which causes dogs to howl in the night, and especiall