74 THE NERVOUS SYSTEM AND ITS CONSERVATION 



it is tit be noted that three pairs (the third, fourth, and 

 sixth in the enumeration) are concerned in the causal ion 

 of movements of the eyes and in l>rin<rmi- about the adjust- 

 ments for varying illumination and for vision at different 

 distances. The six slender muscles which serve to turn 

 each eyeball in whatever direction we desire arc probably 

 provided more liberally with motor nerve-fibers than any 

 other muscles in the body. Our command over them is 

 correspondingly perfect; we do not fall short or overshoot 

 the mark in looking from one object to another. If there is 

 another in<tance of such precision in control of muscles it 

 is the case of those which act upon the cartilages of the. 

 larynx in the trained singer. 



Reference: Lickley, "The Nervous System," Longmans, (In-en A: 

 Co., London, 1912. 



