RESPIRATION. 167 



when they wish to enter a well or vat where they suspect 

 its presence, first sink a lighted candle down. If it burns, 

 there is air, and it is safe for them to descend ; but, if the 

 candle is extinguished, there is no air but carbonic acid 

 gas ; they cannot go down in safety. For want of this pre- 

 caution, some have been suffocated, and even lost their lives. 



387. Probably more have perished from breathing the 

 fumes of charcoal than from breathing any other gas. A 

 pan of coals is sometimes left burning in a small bed-room, 

 which has no open fireplace, while some one sleeps on the bed. 

 The gas given out falls to the floor, and fills the bottom of 

 the room, rising as fast as it is produced, until it reaches the 

 sleeper's head. At first, he suffers -difficulty of breathing, 

 violent pulsations of the heart, which are soon followed by a 

 partial and almost entire suspension of th respiration and 

 of the circulation of the blood. Then the organs of sense 

 lose their power, the sensibility is destroyed, the prostration 

 is extreme, and the want of power of motion so complete 

 that the sufferer seems dead. If removed, he may possibly 

 be restored ; but, if he remains in this gas, destruction of life 

 follows as surely as if the sleeper were overwhelmed with 

 water. 



388. Drowning produces death, not, as is commonly sup- 

 posed, by filling the lungs with water, but because the water 

 prevents the access of air to the respiratory organs, and tho 

 sufferer dies from suffocation. 



389. The effects of limited respiration, and of breathing 

 impure air, have thus far been considered only in the imme- 

 diate depreciation of life, or the production of death, by the 

 mere deficiency of pure, well-oxygenated air. " But often 

 injurious and even fatal consequences afterward come. 

 Some of the survivors of the Black Hole were seized with 

 putrid fever, and subsequently died. Those .who breathe 

 charcoal gas are for some time drowsy, and are apt to fall 

 into a deep sleep, or lethargy, from which it is difficult to 

 rouse them ; and those who live in close rooms have less 

 mental and bodily activity, less sprightliness and energy, 



