xvin THE SPECIAL SENSES AND SENSATIONS 275 



down, or with the head bent over, as when working at 

 a low desk. The habit of reading after going to bed 

 is very injurious. 



6. Reading on trains, on street cars, in carriages, or 

 while walking about is a very severe strain on the 

 muscles of accommodation, and should be avoided. 



7. Books and papers should have large, clear type 

 that is well leaded, good paper, not too highly sized, 

 and lines not to exceed four inches in length. Poor, 

 cheap books, with small, blurred, indistinct type, should 

 be avoided if possible. 



8. The head should always be held erect in reading, 

 with the book or paper nearly on a level with the eyes 

 and about fourteen inches away. Many habitually 

 hold their work too close to the eyes and in that way 

 overtax the muscles of accommodation. 



9. When a small object gets into the eye it should 

 be carefully removed. Often the tears will wash the 

 object toward the inner 



corner of the eye, where 

 it can be seen and easily 

 taken out. If necessary, 

 the lid may be turned in- 

 side out, as shown in the 

 figure, and the object re- 



moved. Do not rub the FIG. 151. The upper lid inverted 



(Zinns). 



eye. 



10. The blackboard, slates, paper, and pencils used in 

 the schools should be of the best quality and kept in good 

 condition, so that no undue eye strain may result, 



