SOME LESSONS ON THE HUMAN BODY 



Reading when weary, or when on trains, or when lying down, 

 severely taxes the eyes and should be avoided. Large re- 

 sponsibilities rest upon architects and builders whose business 

 it is to arrange both for the artificial and for the natural 

 lighting of the rooms and buildings in which people are to 

 live and work. 



It is not especially important that objects in front of 

 pupils in schoolrooms, and of workers in offices and shops 

 and homes, shall be 

 illuminated by light 

 that "comes over the 

 left shoulder." But 

 the illumination must 

 be neither too bright 

 nor too dim, and the 

 light must be so uni- 

 formly diffused that 

 sharply outlined shad- 

 ows do not exist in 

 the room. Any con- 

 scious effort in excluding 

 light from the eyes 

 because it is too glaring, 



or in making out details of objects viewed because 

 the light is too dim, is evidence of something wrong 

 with the illumination of the room. No direct rays 

 of light should be allowed to come into the eyes either 

 from the sun or from electric bulbs. The contraction of 

 the pupil to shut out the excess of light from an unscreened 

 lamp shining directly into one's eyes may result in eyestrain, 

 since too little light can then enter them from the objects 

 upon which one is at work. The glare of the lights of an 

 automobile blinds one to other objects near at hand that are 

 not brightly lit up, because the size of the pupil of the eye 

 adjusts itself to the more intense light. 



FIG. 5. Hard on the eyes. 



