THE BEASON WHY. 231 



' For the Lord seeth not as man seeth ; for man looketh on the outward appear- 

 ance, but the Lord looketh on the heart." SAMUEL xvi. 



962, What are the nerves of sympathy ? 



The nerves of sympathy, or the system of sympathetic nerves, 

 are those which are distributed to the internal organs, and which 

 are independent of the will. They regulate the motions of the 

 heart, the lungs, the stomach, &c., and stimulate the organs of 

 secretion, so that those organs work in harmony with. each, other. 



As the internal organs are all more or less dependent upon each 

 other r and unite their functions for similar ends, it is obvious that 

 there should prevail among them a mutual consciousness of their 

 state. Otherwise, when the stomach had formed chyme, the liver 

 might have no bile ready to fulfil its office ; the absorbents might 

 be in a state of rest at the moment when nutrition was set before 

 them ; and the heart might beat slowly, while the lungs were in 

 active exertion to obtain additional blood to support an active 

 exercise. The sympathetic system of nerves therefore regulates 

 and harmonises these internal functions. 



CHAPTER XLVIII. 



963. Why do we see objects ? 



Because the light which is reflected from them enters OUT eyes 

 and produces images of their forms upon a membrane of nerves 

 called the retina, just as images are produced upon a mirror. 



964. Why does this enable us to see ? 



Because the membrane which receives the images of objects is 

 connected with the optic nerve which transmits to the brain impres- 

 sions made by the reflections of light, just as other nerves convey 

 the effects of feeling, hearing, tasting, &c. 



9G5. Why are ice enabled to move our eyes ? 



Because various muscles are so placed in relation to the eye- 

 ball, that their contraction draws the eye in the direction required. 

 We are thus enabled to adjust the direction of the eye to the position 

 of the objects we desire to see, in other words to set the mirror in 

 tuck a j osili<r~<. that if will receive the re/lection. (See 517 j 



