human intelligence.  Among other feats, it would pick up from the floor and present to the keeper or to a visitor, a stated number of straws up to five.  Many monkeys seem nearly purely destructive in their dealings with objects within their reach; but Leutemann tells of an orang-outang which “tried to put to its proper use whatever was given to him.  To my great surprise he attempted to put on a pair of gloves.  He supported himself on a light walking cane and, when it bent under him, made ridiculous motions to right it again.”  Brehm tells of a chimpanzee: 

“After eating, he at once begins to clean up.  He holds a stick of wood in front of him, or puts his hands in his master’s slippers, and slides about the room, then takes a cloth and scrubs the floor.  Scouring, sweeping, and dusting are his favourite occupations; and, when he once gets hold of the cloth, he never wants to give it up.”

Falkenstein has given a detailed description of a gorilla which was remarkable for his delicacy in eating.

“He would take a cup or glass with the greatest care, using both hands to carry it to his mouth, and setting it down so carefully that I do not remember having lost a single piece of crockery through him, though we had never tried to teach him the use of such vessels, wishing to bring him to Europe as nearly in his natural condition as possible.”

These and a multitude of similar observations which have been made since Huxley wrote are typical of the increase of our knowledge on the habits and capacities of the anthropoid apes.  They all serve to show that in them the instinct for experimental investigation of everything with which they are surrounded, and their imitative faculties are peculiarly great.  The importance of this, from the point of view of Huxley’s argument, is great.  The difference between the instincts of the lower animals and the intelligence of man is that instincts are to a large extent fixed and mechanical.  The proper performance of an instinct demands the presence of exactly the right external conditions for its accomplishment.  In the absence of these conditions, the call to perform the instinctive action is equally great, and results in useless performances.  In many of the higher animals these elaborate instincts are more general in their character, and are supplemented by a considerable but varying aptitude for modification of instinctive action to suit varieties of surrounding circumstances.  As this intelligence becomes more and more developed, the blind, mechanical instinct becomes weaker.  A large number of instances might be given of such instincts modified by dawning intelligence.  The chief factors in producing the change are, as has been shewn by Professor Groos, the possession of a general instinct to imitate and to experiment, and the existence of a period of youth in which the young creature may practise these instincts, and so prepare itself for the more serious purposes of adult life.  The anthropoid apes seem to possess these experimental instincts to an extent much greater than that observed in any other class of animals, and, as they have a long period of youth, they have the opportunity of putting them into practice to the fullest possible extent.