266 MENTAL LIFE OF APES AND MONKEYS 
beyond the reach of his chain he deliberately goes to the 
marble and pushes an arm down between the upright part 
of it and the wall, until he has moved the whole slab 
sufficiently far from the wall to admit of his slipping down 
behind the upright part himself. He then places his back 
against the wall and his four hands against the upright 
part of the marble, and pushes the slab as far as he can 
stretch his long legs. He only does this, however, when he is 
bent on mischief, as the fact of food being beyond the reach 
of his chain does not furnish a strong enough inducement to 
lead him to take so much exertion.”’ 
Another interesting incident in this connection is furnished 
by Prof. Mébius. A chimpanzee, Molli, was confined in a 
wooden cell. When someone from the outside was driving 
a nail into the wall of her cell, and she saw the nail coming 
through the board, she went to her drinking vessel, took it 
in both hands and pounded the nail back again. 
The use of implements for various purposes is, according 
to the testimony of several writers, a not uncommon feature 
of monkey behavior. Prof. Cope, in describing the perform- 
ances of a Cebus capucinus says: . “He then used the strap 
in a novel way. He was accustomed to catch his food with 
his hands when thrown to him. Sometimes it fell short 
three or four feet. One day he seized his strap and took 
pretty correct aim and finally drew the pieces to within 
reach of his hand. This performance he constantly repeats, 
hooking and pulling the articles to him in turns of the strap. 
Sometimes he loses hold of the strap. If the poker is handed 
him he uses it with some skill for the recovery of the strap. 
After punishment the animal would only exert himself in 
this way when not watched; as soon as an eye was directed 
to him he would cease.” | 
Witmer relates that Peter, a trained chimpanzee which 
