MENTAL LIFE OP MONKEYS AND APES 117 



With Sobke the following results were obtained. In forty 

 trials given on two different days, he reached for and obtained 

 the food each time with his left hand. Only by holding the 

 bait well toward the right side of his body was it possible to 

 induce him to use the right hand. So far as may be judged 

 from these observations and from others in connection with 

 the experiments, this animal is definitely left-handed. 



With Skirrl the results are strikingly different. As stated 

 above, he used the hammer consistently with his left hand, but 

 in l^wenty attempts to obtain food by reaching, he used his 

 right hand seventeen times and his left only three times. It 

 was quite as difficult to induce him to use his left hand for this 

 purpose as it was to induce Sobke to use his right. We must 

 therefore conclude that Skirrl is right-handed in connection with 

 certain movements and left-handed in others. 



The monkey named Gertie in the reaching experiment con- 

 sistently used her left hand, never once using the right. 



Jimmie, so far as it was possible to make tests with him, 

 also used his left hand, but it should be said that the results 

 are unsatisfactory because he was at the time extremely pug- 

 nacious and paid attention to the experimenter rather than 

 to the food. 



Scotty, in the first series of ten trials, used his right hand 

 eight times, his left twice. In the second series, given the 

 following day, he used the right hand three times and the left 

 seven times. From this we should have to infer that he is 

 ambidextrous. 



A female rhesus monkey which had been brought to the labo- 

 ratory only a few days previously showed a preference for the 

 right hand by the use of it fourteen times to six. 



In cormection with these data which are, I should repeat, 

 too scanty to be of any considerable value, I wish to describe 

 my own experience. Although naturally left-handed, I am by 

 training right-handed to the extent of having been able to use 

 my hands in writing and in various other activities equally well 

 at the age of twelve. I am at present ambidextrous in that 

 there are many things which I do with equal readiness and 

 skill with either hand. Delicate, exact, and finely coordinated 

 movements, such as those of writing and using surgical instru- 

 ments, I perform always with my left hand, while grosser move- 



