30 APES, MONKEYS, AND LEMURS 



netting of her cage. After this climax the utterance of a few grunts terminated 

 the performance. 



Some time previous to 1889, it occurred to Dr. Romanes (from whose account 

 we are paraphrasing) that "Sally" would be a good subject to test the power of 

 the simian intelligence by a series of special experiments. It was found, however, 

 that such experiments were seriously hampered by the effects on the creature of the 

 visits of the numbers of people who were constantly passing in and out of the room 

 in which she was kept ; and there is consequently but little doubt that, under more 

 favorable circumstances, the results obtained would have been more remarkable 

 than they are. Dr. Romanes, having secured the assistance of the keepers, caused 

 them to ask "Sally " repeatedly for one, two, or three straws, which she was to pick 

 up and hold out from among the litter strewing her cage. The number of straws 

 asked for was constantly varied, and never followed by any regular order; and when 

 the correct number was presented the animal was rewarded by a piece of fruit, 

 while if the number was incorrect her offer was refused. "In this way," observes 

 Dr. Romanes,* " the ape was taught to associate these three numbers with their 

 names. Lastly, if two or three straws were demanded, she was taught to hold one 

 or two in her mouth until she had picked up the remaining straw, and then to 

 hand the two or three straws together. This prevented any error arising from her 

 interpretation of vocal tones. As soon as the animal understood what was required, 

 and had learned to associate these three numbers with their names, she never failed 

 to give the number of straws asked for. Her education was then extended in a 

 similar manner from three to four, and from four to five straws. Here I allowed 

 her education to terminate. But more recently one of the keepers has endeavored 

 to advance her instruction as far as ten. The result, however, is what might have 

 been anticipated. Although she very rarely makes any mistake in handing out 

 one, two, three, four, or five straws, according to the number asked for, and al- 

 though she is usually accurate in handing out as many as six or seven, when the 

 numbers eight, nine, or ten are named, the result becomes more and more uncertain, 

 so as to be suggestive of guesswork. It is evident, however, that she understands 

 the words seven, eight, nine, and ten to betoken numbers higher than those below 

 them ; and if she is asked for any of these numbers, she gives some number that is 

 above six and not more than ten ; but there is no such constant accuracy displayed 

 in handing out the exact number named, as is the case below six. On the whole, 

 then, while there is no doubt that this animal can accurately compute any number of 

 straws up to five, beyond five the accuracy of her computation becomes progressively 

 diminished. It is to be noticed that the ape exhibits some idea of multiplication ; 

 for she very frequently doubles over a long straw so as to make it appear as two 

 straws. Any of the rare errors which she makes in dealing with numbers below 

 six are almost invariably due to her thus endeavoring to duplicate her straws. In 

 this connection it is to be remembered that, owing to the method above described, 

 when any high number is demanded, a considerable tax is imposed upon her 

 patience ; and as her movements are deliberate, while her store of patience is small, 



*We have somewhat abbreviated the extract. 



