344 ELEMENTS OF PHYSIOLOGY 



622. Care of the Eyes. Sight is Priceless. (When 

 reading is mentioned in these suggestions, it is meant 

 to include such work as writing, sewing, embroidering, 

 etc.) 



1. The light should be steady, not flickering ; we should 

 not read after sunset by the fading twilight ; we should not 

 read with the sunlight falling on the book; we should 

 not read facing a window or with a light directly in front, 

 unless the eyes are protected by a shade. The lamp should 

 also be shaded. Incandescent electric lights give an uneven 

 light, because of the shadow cast by the filament; a shade 

 diffuses its light more evenly and protects from the glare. 

 Light curtains diffuse the light evenly, but dark curtains 

 cause lights and shadows. 



2. The state of the eyes is of importance : We should 

 not read when tired or sleepy; when convalescing from 

 an illness; with the head bent down; or heated by the 

 burner ; when the eyes are sore ; when they are tired, 

 unless we rest them every few minutes by looking at 

 far objects ; when riding in jolting cars and carriages ; 

 when the circulation is impeded by tight clothing around 

 the neck. 



" Tobacco blindness " sometimes results from smoking. 

 The first symptom is color blindness, which is followed by 

 haziness of vision, and finally, by partial or complete loss 

 of sight. 



3. The kind of work is of importance : The type 

 from which books are printed should be large. The 

 paper should not be pure white or glazed, but a neu- 

 tral tint; it should be opaque, so that the printing will 

 not show through from the reverse page : the lines 

 should not be more than four and a half inches long. 

 Publishers of magazines are the worst offenders in using 

 shiny glazed paper because it brings out the beauty of 

 fine engravings. 



