6oo LIFE : OUTLINES OF GENERAL BIOLOGY 



tat ion of what would fill the gap, and might search for it in a 

 widened environment. Not that any hard-and-fast line can be 

 drawn ; for there is the well-known case of Miss Cunningham's young 

 gorilla, who, after sulking a little on being refused a seat on her lap, 

 searched round the room for a newspaper, which he proceeded to 

 spread as an apron over his teacher's dress. 



The st^cond handicap is the merely incipient character of ape 

 language. Chimpanzees have many words indicative of particular 

 experiences, such as meals and danger, or of particular emotions, 

 such as joy and resentment ; but there is no expression of a judgment 

 in even the tiniest sentence, and there is not, as is seen in parrots, 

 any social imitation of particular sounds. But it is language that 

 widens the folding-doors of the mind that necessity and visualisation 

 have opened. 



Inst.vnces of Intelligence. — It is all very well to say that we 

 mean by intelligent behaviour a chain of actions which cannot 

 be adequately described without crediting the animal with some 

 degree of perceptual inference ; but it is necessary to adduce definite 

 cases that illustrate the contrast between this and instinct. 



We begin with a previously unpublished case, which we owe to a 

 careful observer, Arthur H. Sim. A cock homer pigeon was due to 

 relieve the brooding hen, who was sitting in a dovecot. This had an 

 alighting-board at the entrance, and the door itself was a sliding 

 shutter working in a bevelled rail. As the entrance was half-closed, 

 the cock pigeon got his head and shoulders in, and succeeded 

 in shoving the shutter along. But the observer frustrated his success- 

 ful entry and put him outside again, adjusting the shutter in the 

 original position. Whereupon the pigeon repeated the effort with 

 success, and this was done several times in the course of a few 

 minutes, the bird becoming increasingly expert. 



After a short time the experiment was varied, and a small piece 

 of wood about two inches long and half an inch broad was laid in 

 the bevelled rail in such a way that the door could not be pushed 

 along far enough to let the pigeon in. After some fruitless pushing, 

 the pigeon seized the piece of wood in his Ix^ak and threw it on the 

 ground. He then slid the door along and entered the dovecot. 



But he was not allowed to settle down, and the jx^rformance was 

 repeated several times in the course of a few minutes. As the bird 

 was always baulked of his reward, he gave up trying, and remained 

 passive on the alighting-board for almost ten minutes, the observer 

 standing three or four yards away. 



The next step was of much interest. The observer went into his 

 house close by and watched from a window. As soon as he had 

 reached his post of observation he saw the pigeon seize the piece 

 of wood and toss it into the air, afterwards effecting entrance as he 



