TOUCH. 



water into the ear; it causes a pea or bean to swell, and 

 makes its removal very difficult. 



Deafness may be caused in many ways: by disease of 

 the auditory nerve, by disease of the labyrinth or of the 

 tympanum, by stoppage of the outer passage by wax or 

 some foreign object, or by inflammation and swelling of 

 the membrane lining the Eustachian tubes. Swollen 

 tonsils (p. 101). or a cold which has settled on the throat, 

 or smoking, very often cause deafness in the way last 

 mentioned. If the auditory nerve or the internal ear are 

 at fault, the deafness may be incurable. In most other 

 cases, cure is possible with medical aid. In the case of 

 a cold, the cure usually occurs of itself if you have a 

 little patience. 



17. Touch, or the Pressure-Sense. Many sensory nerves 

 end in the skin, and through it we get several kinds of 

 sensation; touch, heat and cold, and/0/y and we can with 

 more or less accuracy say from what parts of the skin 

 they have come. The interior of the mouth also pos- 

 sesses these feelings. Through touch, we recognize pres- 

 sure on the skin, and the force of the pressure; the soft- 

 ness or hardness, roughness or smoothness, of the body 

 producing it; and the form of this body, when it is not 

 too large to be felt all over. The nerves of touch are 

 very numerous. A great many of them end inside 

 papillae of the dermis(p. 63). 



18. The Delicacy of the Sense of Touch is very different 



some foreign body into its ear ? Name some of the causes of deaf- 

 ness. How may swollen tonsils cause deafness ? When is deafness 

 apt to be incurable ? 



17. What sensations do we get from the skin ? What other part 

 of the body gives rise to these sensations? What do we recognize 

 through touch ? Where do many of the nerves of touch end ? 



