idual and particular odor (which I do not
believe), it is hardly possible, nay, it is impossible, that the dog's
sensorium had recognized and retained these different scents in the
short time which had elapsed since their birth. It is much more
reasonable to suppose that the dog knew that she had given birth to six
young ones, and that she had counted them when they had been removed to
their new home. Again, it is a well-known fact that a dog can retain
only one scent at a time; hence, this fact alone would militate somewhat
against the idea that the sense of smell was the detecting agent in this
case. Nor could it have been the sense of touch; the mother could not
have possibly familiarized herself with the individual form of each
puppy in so short space of time. It is folly to suppose that each young
one had a distinctive taste or flavor; hence the sense of taste must
also be eliminated. Thus, by exclusion, there remains but one faculty,
the faculty of computing, to account for the dog's actions.

Several years ago there lived in Cincinnati a mule which was employed
by a street railway company in hauling cars up a steep incline. This
animal was hitched in front of the regular team, and unhitched as soon
as the car arrived at the top of the hill. It made a certain number of
trips in the forenoon (I have forgotten the number, but will say fifty
for the sake of convenience), and a like number in the afternoon,
resting for an hour at noon. As soon as the mule completed its fiftieth
trip, it marched away to its stable without orders from its driver. To
show that it was not influenced by the sound of factory whistles and
bells, the following remarkable action on the part of this animal is
vouched for by the superintendent of the line, who gave me these data.
On a certain occasion, during a musical festival, this mule was
transferred to the night shift, and the very instant it completed its
fiftieth trip it started for the stables. It took the combined efforts
of several men to make it return to its duty. At night there were no
bells or whistles to inform the creature that "quitting-time" had come;
it thought the time for rest and food had arrived as soon as it had
completed its fifty trips.[88]

[88] These data were given to me at a certain club banquet where I had
no facilities for noting them down. I have endeavored to locate the
superintendent in question, but without success; I believe, however,
that he gave th