column of the partition, and very deftly bent two of the iron bars
outward far enough so that he could easily thrust his head outside
and have his coveted look.

One of our later and largest orangs made a specialty of twisting
the straw of his bedding into a rope six or seven feet long, then
throwing it over his trapeze bar and swinging by it, forward and
back.

Time and space will not permit the enumeration of the various
things done by that ape of mechanical mind with his swinging rope
and his trapeze, with ropes of straw _twisted by himself,_
with keys, locks, hammer, nails and boxes. Any man who can witness
such manifestations as those described above, and deny the
existence in the animal of an ability to reason from cause to
effect, must be prepared to deny the evidence of his own senses.

The individual variations between orangs, as also between
chimpanzees, are great and striking. It may with truth be said
that no two individuals of either species are really quite alike
in physiognomy, temperament and mental capacity. As subjects for
the experimental psychologist, it is difficult to see how any
other could be found that would be even a good second in living
interest to the great apes. The facts thus far recorded, so I
believe, present only a suggestion of the rich results that await
the patient scientific investigator. In the year 1915 Dr. Robert
M. Yerkes, of Harvard University, conducted at Montecito,
southern California, in a comfortable primate laboratory, six
months of continuous and diligent experiments on the behavior of
orang-utans and monkeys. His report, published under the title of