RESPIRATION. 165 



deck in the morning, even in cold and stormy weather, to 

 inhale the fresh air, and remove the oppression, and recover 

 themselves from the weariness of their night's lodging. 



CHAPTER XV. 



Crowded Audiences uneasy and impatient. Children in unventi- 

 lated School-rooms uneasy and dull. Deficiency of pure Air de- 

 preciates, and total Want of it extinguishes Life. Breathing Car- 

 bonic Acid Gas. Drowning. Breathing impure Air impairs 

 Constitution. Consumption among Females. 



383. A CROWDED audience in a lecture-room or concert- 

 hall, after a while, become weary and uneasy, and indiffer- 

 ent to the lecture or the music before them, although the one 

 may still be as interesting, and the other as exquisite, as in 

 the beginning. Their senses grow dull ; they neither under- 

 stand the arguments of the speaker so readily, nor enjoy the 

 harmonies of the music so keenly ; and yet they are more im- 

 patient of mistakes and imperfections. Some complain that 

 they never return from such assemblies without a headache. 

 The weariness, the restlessness, the impatience, and the pain, 

 all arise from one and the same cause the foulness of the 

 air. For want of oxygen, the blood is not purified ; then 

 impure blood is sent to the muscles, and cannot strengthen 

 them to support the body ; the same is sent to the brain, and 

 irritates it, and disturbs the nervous system. 



384. After children have sat in crowded school rooms for 

 some time they grow dull and heavy. Their blood is not 

 then relieved of its carbon and hydrogen : impure blood is 

 sent back to the heart ; and thence it is sent again, with all 

 its imperfections, to the whole body. The brain, being fed 

 with this corrupted and corrupting blood, instead of being 

 enlivened, is made inactive and heavy. It then works lan- 

 guidly, or refuses to work at all. The children become un- 

 easy, restless, and oftentimes sleepy; they are averse to 



