THE SPECIAL SENSES 315 



temperature, and its security seems to demand the continued 

 presence of the "warm" covering. As a consequence of its 

 presence, sounds are not naturally conveyed, and the sensitive- 

 ness of the nerve of hearing is gradually impaired. 



108. The chief source of injury, however, to the ear is 

 from the introduction of solid substances into the auditory 

 canal, with the design of removing insects or other foreign 

 objects that have found their way into the ear, or with the 

 design of scraping out the ear-wax. For displacing a foreign 

 object, it is usually sufficient to syringe the ear gently with 

 warm water, the head being so held that the fluid easily 

 escapes. If a live insect has gained entrance to the ear, it 

 may first be suffocated by pouring a little oil upon it, and 

 afterward removed by syringing the ear as just mentioned. 



109. The removal of ear-wax is generally unnecessary ; for, 

 as we have before seen, Nature provides that the excess of it 

 shall become dry, and then spontaneously fall out in the form 

 of fine scales. The danger from the introduction of solid 

 implements into the outer ear is chiefly found in the fact that 

 the membrane which lies at the bottom of it is very fragile, 

 and that any injury of it is liable to impair permanently the 

 hearing of the injured ear. 



110. How Alcohol affects the Special Senses. The narcotic 

 or benumbing influence of alcohol is felt by all forms of ner- 

 vous tissue, and among them the nerves of special sense. Vision 

 is more susceptible of injury by this poison than any of the 

 other senses, and it may be either slightly impaired or wholly 

 lost. There is, in such cases, a progressive loss of power in 

 the optic nerve that can only be remedied by a perpetual 

 abandonment, on the part of the sufferer, of alcoholic drink ; 

 and even this must not be delayed too long after dimness of 

 sight has commenced. 



111. Alcohol and Color-Blindness. Progressive loss of 

 color-perception has been noticed by physicians in persons 



108. Chief source of injury to the ear ? Directions for removing foreign objects from 

 the ear ? Of a live insect ? 109. The removal of ear-wax ? 



110. Do those who drink alcohol have good vision ? 



111. What about their perception of color ? 



