HUNTING CHIMPANZEES. 93 



watching their play, and we were so completely hidden 

 that none of them suspected our presence. After seeing 

 them in this way, I became convinced that the natives' 

 opinion of their intelligence, and their obedience to the 

 recognized chiefs of their strange communities, is justi- 

 fied by the facts. This city of theirs proves their social 

 instinct, and its very existence makes certain tacit rules .j; 



of conduct probable. It is this social life that especially } 



distinguishes the chimpanzee from the gorilla, who lives 

 only with his family and never in connnunities. 



