142 SHEPHERD IVORY FRANZ 



only about 3 cm. apart, and at other times they were as much 

 as 10 cm. apart. At all times they were sufficiently separated 

 so that both pieces were to be obtained only with difficulty 

 in one operation. 



Observations of the number of times each hand was used 

 were made with six animals. Three of the monkeys were ob- 

 served from the beginning until the end of the experimental 

 series, and the other three were observed after they had formed 

 the habit of taking one piece (the sweet) .and disregarding the 

 other (the bitter). Observations of two of the animals were 

 continued after the extirpation of parts of the occipital lobes. 

 The general results of the observations are given in tables I 

 and II. 



TABLE I 



Total Number of Times Each Monkey Used Right and Left Hands 

 During Period of Observation, Previous to Operation 

 Monkey Right hand Left hand Totals 



Totals 419 738 1157 



TABLE II 



Total Number of Times Each of Two Monkeys Used Right and Left 

 Hands During Period of Observation Following Operation 

 Monkey Right hand Left hand Totals 



1 108 21 129 



8 30 30 



Totals 138 21 159 



Monkeys 1, 3 and 8 were the animals which were observed 

 throughout the period of training, and monkeys 2, 6 and 7 

 were observed only after the habit of taking the sweet food 

 was established. The results from the first set of animals are 

 the more interesting on account of the greater number of ob- 

 servations, although the results from the second set show the 

 same general tendency. Table I indicates that monkeys 1 and 

 7 were ambidextrous; monkeys 3, 6 and 8 showed a decided 

 preference for the left hand, and monkey 2 is in a doubtful 



