242 GEOEGB JOHN EOMANES 1888- 



Avill have to wait in vain, should the birds have ever 

 been shot at from the hut on a previous occasion. 

 Leroy then goes on to say : ' To deceive this suspicious 

 bird, the plan was hit upon of sending two men into 

 the watch-house, one of whom passed out while the 

 other remained ; but the rook counted and kept her 

 distance. The next day three went, and again she 

 perceived that only two returned. In fine, it was 

 found necessary to send five or six men to the watch- 

 iioufie in order to throw out her calculation.' 



Finding it on this testimony not incredible that a 

 bird could count as far as five, I thought it worth 

 while to try what might be done with a more 

 intelhgent animal in this connection. Accordingly, 

 about a year ago, I began, with the assistance of the 

 keeper, to instruct the chimpanzee at the Zoological 

 Gardens in the art of computation. The method 

 adopted was to ask her for one, two, three, four, or 

 five straws, which she was to pick up and hand out 

 from among the litter in her cage. Of course, no 

 constant order was observed in making these requests, 

 but whenever she handed a number not asked for her 

 offer was refused. In this way the animal learnt to 

 associate the numbers with their names. Lastly, if 

 more than one straw were asked for she was taught 

 to hold the others in her mouth until the required 

 number was complete, and then to dehver the whole 

 at once. This method prevented any possible error 

 arising from her interpretation of vocal tones, an 

 error which might well have arisen if each straw had 

 been asked for separately. 



After a few weeks' continuous instruction the ape 



