452 ^Journal of Comparative Neurology and Psychology. 



can be frightened from fields by scarecrows, only the bird of prey 

 recognizes its victim in the far distance, only amongst birds do we 

 find creatures which, like the carrier pigeons, retrace the path once 

 seen. 



Everyone who in winter strews crumbs of bread from a window 

 observes how upon all sides the birds watch his action, but approach 

 only after he has closed the window. 



Accordingly these animals, which are the first to possess an 

 optic tract leading from the palaeencephalon into the cortex, are 

 likewise the first to so far understand and retain optic impressions 

 that they may long afterward be employed to bring about rela- 

 tively complicated actions depending upon associations of many 

 kinds. 



But when Schrader deprived his falcon of its cortex it fell at 

 once into the condition of a palaeencephalic animal. Running 

 mice were readily caughtby the injured bird, but mice which had 

 crept under the falcon's wings remained unrecognized and gradu- 

 ally devoured their host, which, as a merely palaeencephalic animal, 

 could no longer recognize them associatively. 



Birds hear very well. It is probably only a palaeencephalic 

 hearing when the female follows the call of the male; but magpies, 

 ravens, and parrots learn to come when their names are called 

 and birds of many kinds learn to imitate whistled melodies or 

 even pronounced words. In spite of many anecdotes, there is 

 as yet no conclusive proof that parrots understand language, but 

 there can be no doubt that they employ the same words upon 

 similar occasions. 



It is anatomically uncertain if the oral mechanism is connected 

 with the cortex, and the behavior of the animals scarcely indicates 

 that it is. The action of a bird in digging up worms which are 

 six centimeters under ground can just as well be accomplished 

 through the mechanism of the palaeencephalon. 



Quite new as compared to the reptiles are certain indications 

 of true inteUigence. Of course it is difficult here to avoid being 

 deceived as to the significance of acts. But when a parrot learns 

 always to plunge its hard bread into water before eating, and when 

 animals which have been repeatedly disturbed at one nesting 

 place remove the nest and seek a place inaccessible to the danger 

 first experienced, we can find no other name for this kind of associa- 

 tion-formation than inteUigence. This inteUigence is very clearly 



