74 
MANUAL OF NATURE STUDY. 
light. Long-continued looking at one object. 
Looking at bright objects like the reflection of light 
from a mirror, or from white wall or paper. Effect 
of trying to read or write with insufficient light, 
e. g.—in dusk of the evening. 
Near sightedness and cross-eyes should receive 
proper attention. 
2. The care of ears. Next to the eyes, the ears 
are most important, and should receive our atten¬ 
tion. The ear should be taught in its three parts, 
external , middle and internal. The outer ear gath¬ 
ers the sound waves and therefore should be clean. 
The wax is of use in keeping out insects and pro¬ 
tecting the internal ear from exposure to cold air. 
While it should not be removed entirely, yet it 
should not be allowed to harden at the opening and 
thus clog up the passage way, or to create too much 
pressure upon the tympanum. 
Children should be cautioned against the practise 
of screaming or whistling in another’s ear. Such 
practise is dangerous to the ear. Catarrh causes 
deafness, hence care should be taken to prevent 
taking cold. Do not pick the ear with a pin or 
other hard substance. Avoid the use of tobacco, as 
that will produce inflammation in the ear, and dry 
the tympanum and thereby cause confusion of 
sounds. 
