THE SPECIAL SENSES 301 



situation of the most important parts of the mechanism of the 

 ear the length of its cavity, its partitions, the hardness of 

 its walls, and its communication with the atmosphere ; all 

 these provisions rendering unnecessary any supervision or care 

 on our part in reference to the interior of the ear. But in 

 respect to its external parts, which are under our control and 

 within the reach of harm, it is otherwise. We may both 

 observe the dangers which threaten them, and learn the means 

 necessary to protect them. 



105. Caution. One source of danger to the hearing consists 

 in lowering the temperature of the ear, especially by the intro- 

 duction of cold water into the auditory canal. Every one is 

 familiar with the unpleasant sensation of distension, and the 

 confusion of sounds which accompany the filling of the ear 

 with water when bathing : the weight of the water within it 

 really distends the membrane, and the cold chills the adjacent 

 sensitive parts. It is not surprising, therefore, that the fre- 

 quent introduction of cold water, and its continued presence in 

 the ear, enfeebles the sense of hearing. Care should be taken 

 to remove water from the ear after bathing, by holding the 

 head on one side, and, at the same time, slightly expanding 

 the outer orifice, so that the fluid may run out. For a like 

 reason, the hair about the ears should not be allowed to remain 

 wet, but should be thoroughly dried as soon 'as possible. 



106. It may be stated as a general rule, to which there are 

 but few exceptions, that no cold liquid should ever be allowed 

 to enter the ear. When a wash or injection is rendered neces- 

 sary, it should always be warmed before use. The introduction 

 of cold air is likewise hurtful, especially when it pours through 

 a crevice directly into the ear, as it may often do through the 

 broken or partially closed window of a car. The avoidance of 

 this evil gives rise to another almost as great, namely, the 

 introduction of cotton or other soft substances into the ear to 

 prevent it from "catching cold." This kind of protection 

 tends to make the part unnaturally susceptible to changes of 



105. Danger to which hearing may be subjected ? Advice. 



106. The general rule as to the use of water, for the ear ? 



