THE KKASOX WHY. 239 



1 Apply thine heart unto instruction, and thine ears to the words of 

 knowledge." PBOVEKBS xxiii. 



when the blood flows unduly through the vessels of the ear it 

 produces a slight sound. 



989. Why do people become deaf? 



Because the ear may be injured in various ways : the tympanum 

 may be impaired, the fluid of the ear dried up, or the nerves be 

 pressed upon by swellings in the surrounding parts. When, 

 therefore, the mechanism of hearing is impaired, the sense of 

 hearing becomes weakened, or altogether lost. 



990. Why do persons accustomed to loud noises feel no 

 inconvenience from them ? 



Because the sensitiveness of the nerves of the ear becomes 

 deadened. They do not convey to the brain such intense impulses 

 when they are frequently acted upon by loud sounds. 



991. Why do persons engaged in battle often lose their 

 hearing ? 



Because the vibrations caused by the sounds of artillery are so 

 violent that they overpower the mechanism of the ear, and 

 frequently rupture the connection of the fine nervous filaments 

 with the textures through which they spread. 



The violent concussions of the air produced by volleys of cannon, or by loud 

 peals of thunder, have an overpowering effect upon persons nervously con- 

 stituted, and upon the organ of hearing, which is more especially affected. As 

 persons have been struck blind by intense light, so others have been deafened 

 by intense sounds. In 1697 a butcher's dog was killed by the noise of the 

 firing to celebrate the proclamation of peace. Two troops of horse were 

 dismounted, and drawu up in a line to fire volleys. At the moment of the 

 first volley a large and courageous mastiff, belonging to a butcher, was lying 

 asleep before the fire. At the noise of the first volley the dog started up, andran 

 into another room, where it hid itself behind a bed ; on the firing of the second 

 volley, it ran several times bout the room, trembling violently ; and when the 

 bird volley was fired it ran around once or twice with great voilence, and theu 

 dropped down dead, with blood flowing from its mouth and nose. Persona 

 who are painfully affected by loud noises should put a little wool in their can 

 when such noises are occurring; they will thereby save themselves from 

 temporary inconvenience, and probably preserve the sense of hearing from 

 permanent injury. 



992. Why do ice smell ? 



Because minute particles of matter, diffused in the air, ccine in 



