176 THE HUMAN BODY. 



COLOR-BLINDNESS. 



17, Not a few people are color-blind. Some can not 

 distinguish any colors. Others can not recognize a par- 

 ticular color, as red or blue, confounding it with other 

 colors. If a person is color-blind, it is very desirable to 

 know it. An engineer on a railroad, who could not tell a 

 red light from a green one, would be a dangerous person. 



EFFECTS OF ALCOHOL AND NARCOTICS. 



SECTION V. 1, A clear eye and a good complexion 

 are tokens of health. When the blood is impure, the 

 skin loses its fresh and delicate appearance. Indulgence 

 in alcoholic drinks flushes the face, and often marks it 

 with blotches and pimples. Narcotics give a sallow hue 

 to the skin. 



A blear eye is a characteristic mark of a toper. " Who 

 hath redness of eyes ? They that tarry long at the wine." 



The structure of the eye and the ear illustrate the 

 delicacy and nice adaptation of our bodies. We are 

 wonderfully made, and it is crime as well as folly to blunt 

 our finer perceptions, and abuse our various organs, by 

 narcotics or alcoholic stimulants. We should rather 

 cherish and cultivate them by obedience to every law 

 of health, that they may be, as they were designed to be, 

 the servants and instruments of our higher nature. 



QUESTIONS. 



SECTION I. 1. Name some qualities of the skin. 



2, What is a blister? Is the top layer of the skin sensitive? 

 Are there any blood-vessels in the top layer? Are there any 

 nerves or blood-vessels in the deep layer? 



