OUR FACE FROM FISH TO MAN 



trees. Starting with all this experience the eyes 

 of the first true man not only cooperated with 

 the hands, but filled the brain with memory 

 pictures, and these, on the principle of conditioned 

 reflexes, came to be associated in definite com- 

 binations with the memories of vocally produced 

 sounds. Thus mans eyes and ears, rather than his 

 nose, provided him with the means of rising above 

 the endless round of life known to his predecessors, of 

 turning his observational powers upon himself, and 

 eventually of foreseeing not only the immediate but 

 also some of the distant effects of his own activities. 



Primitive Sound Recorders 



The human organ of hearing (Fig. 103) consists 

 of three main parts: (1) the external ear, for collect- 

 ing the sound waves; (2) the middle ear, including 

 the tympanic or drum-membrane and the tym- 

 panum or middle-ear chamber, the latter con- 

 taining the three auditory ossicles, the ofiice of 

 which is to transmit the vibrations of the drum 

 membrane to the inner ear; (3) the inner ear, or 

 labyrinth, comprising (a) the three semicircular 

 canals with their basal connecting chamber or 



utriculus, the canals and utriculus being concerned 



202 



