I5O APPLIED PHYSIOLOGY 



drumhead, just as hitting a drum too hard may spoil it. 

 This may cause deafness. You should never strike a per- 

 son upon the ears in play. A very loud noise may also 

 burst the ear drum, or at least cause pain and deafness. 

 You should stop your ears when you expect a loud noise. 

 Men who shoot cannon often have to put cotton into their 

 ears before they fire. 



Cold water in the ear may cause an earache. When 

 you get water in your ear while you are in swimming, turn 

 your head to one side and shake it so that the water will 

 run out. 



Do not put anything into your ear. It is very hard to 

 get a bean or a stone out again. Cotton in the ear makes 

 the ear tender and causes more colds than it prevents. 



If the ears run with matter, wash them out with clean 

 water and borax. Do not plug them up with cotton or 

 anything else, for that will keep the matter in. 



300. Ear wax. The outer tube of the ear produces a 

 kind of bitter wax. This keeps insects from crawling into 

 the ear. Sometimes it collects into a mass. By trying to 

 get it out you may force it farther into the ear and against 

 the drumhead. Then you will become partly deaf. 



You should not pick your ears, for you may hurt the 

 drumhead. The wax naturally grows outward, and so does 

 not collect in the ear if it is left alone. 



301. The nose. We smell with the nose. In the upper 

 part of the nose fine nerves are spread out beneath the 

 epithelium. When a vapor in the air soaks through the 

 wet sides of the nose, it touches the nerves and produces 

 the sense of smell. 



In order to have a smell, a substance must become a 

 vapor. So those substances which cannot become a vapor 

 have no smell. A very small amount of a substance in the 



