126 THE CREATION OF MATTER 



colour impressions made. Reaching the eye in numbers 

 far beyond any that can be numbered, they enter it in 

 perfect order. The eye is a little round ball. In it are 

 two lenses filled with crystalline liquids, and many 

 arrangements for effective working. At its back are the 

 retina and nerves, which pass to the brain and convey 

 the motions to it. 



In sound perceptions there are the motions generated 

 by blows, voices, and instruments. These are carried by 

 the air, and enter the ear. The ear has many parts. 

 There is the canal, the drum membrane, a cavity within 

 it, surrounded by bones, and filled with air, which is 

 renewed by a tube passing to the pharynx. Further 

 inward are a hammer, an anvil, and a stirrup, a second 

 membrane and labyrinth filled with liquid, in which are 

 nerves in many thousands running to the brain. Sound 

 waves enter by the canal, strike the membrane, and 

 agitate the air within. By it the hammer is made to 

 strike the anvil, the anvil the stirrup, the stirrup the 

 second drum, and so the motions are communicated to 

 the liquid within, and from it pass along the nerves to 

 the brain. 



Thus also through their organs do the motions reach 

 the brain, which cause the sensations of smell, taste, and 

 touch. 



Among organs the brain is the most complex. It is 

 the seat of perception and all mental energy. Without 

 its suitable action, consciousness in the body is impos- 

 sible. It is large in size. In man its average weight is 

 49J ounces, in woman 44. In the surface of the brain 

 is grey, cortical matter, cellular in form, and closely 

 connected with mental action. Within is white matter, 

 consisting of masses of fibres regarded as transmissive. 

 The ingoing nerves from the senses end in the grey 



