RESPIRATION AND THE VOICE. 137 



a large room, such as a church, many people can remain 

 for a long time without suffering, even if the air is not 

 changed. They may not be aware that it is growing im- 

 pure, though one coming in from out of doors would know 

 it at once. If the room is small, the air must be constantly 

 changed, or they will be distressed. 



6, The Black Hole, at Calcutta, was a room in which 

 one hundred and forty -six men were confined over night. 

 It was eighteen feet square, and had two small windows, 

 through which the air did not come freely. Their suffer- 

 ings were intense, arid only twenty-three of them were 

 alive in the morning. 



7, Nothing is so free and abundant as fresh air; and yet 

 we all suffer frequently, and many suffer constantly, for 

 want of it. We should always remember its importance. 

 It is possible to become accustomed to close rooms. We 

 may not know what is the cause of a drowsy head, a disin- 

 clination to exercise, and general ill health, while it is 

 simply lack of fresh air. Sleeping-rooms, in which we 

 spend a third of every day, unconscious of the state of 

 the air, should be well ventilated. 



8, It is very difficult to get fresh air enough into our 

 dwellings and public buildings, and, at the same time, to 

 avoid draughts, and keep warm. Ventilation is almost a 

 science by itself. There are many ways, but no one way 

 which will do for every room. But if we all bear in mind 

 the necessity of fresh air, and use our judgment and 

 ingenuity, we shall get it. 



THE VOICE. 



SECTION VII. 1, The organs of breathing are, at the 

 same time, organs of voice. The larynx is especially the 



