NO. 27, INFLUENCE OF ATMOSPHERE ON HEALTH 37 



headache, throbbing, flushing or marked hyperpncea. At the end 

 of the experiment the bag contained o.o per cent C0 2 and 8.7 per 

 cent O, ; in another experiment only 6.7 per cent O a . They blind- 

 folded the subject and let him breathe alternately air containing 7 

 per cent C0 2 and 11.3 per cent 2 and air containing almost no 

 C0 2 and 9.5 per cent 2 . The first caused hyperpncea and the 

 second relieved it. 



In another experiment the subject breathed from a bag filled with 

 hydrogen. At 30" he was getting blue ; at 40" he was blue and 

 hyperpnceic ; at 50" he lost his senses and fell down in his chair, 

 but recovered at once without headache or any other symptoms. 



They placed two large rabbits in a chamber, and drew a current 

 of air through this, and through a chamber in which were two small 

 rabbits. No effect was produced. They took five bottles, each of a 

 capacity of 1 to 1.5 liters, and connected these by tubes and, placing 

 a mouse in each, drew a current of air through the whole series. 

 The mice were exposed to this for 53 hours without harm. 



In another experiment, lasting 3 days, the mice remained normal, 

 and yet the percentage of C0 2 in the last bottle varied from 2.4 to 

 5.2 per cent, averaging about 3 per cent, during the whole period. 



Beu also repeated the Brown-Sequard experiments and attributed 

 the death of their animals to accumulation of moisture and change 

 of temperature. His animals became wet and cold, and the protec- 

 tion afforded by the H 2 S0 4 absorption tube Beu attributed to the 

 removal of moisture. 



Bauer carried out the same kind of experiment but inserted be- 

 tween the fourth and fifth cages an H 2 S0 4 absorption tube, and be- 

 tween the fifth and sixth cages soda-lime absorption tubes. The 

 sixth animal remained alive, while the fifth died, proving that excess 

 of carbonic acid was the cause of death. 



Lubbert and Peters reached the same conclusion. Between the 

 third and fourth flasks they placed a tube containing red-hot cupric 

 oxide to remove the organic matter, and other tubes for cooling the 

 air and drying it. The animal in the fifth jar died when the C< > 2 

 increased to 11 to 12 per cent. When a soda-lime tube was inter- 

 posed between the fourth and fifth cages, the animal in the fifth lived. 

 None of these researches yielded any evidence of organic poison in 

 the exhaled air. 



Billings, Weir Mitchell, and Bergey investigated the duration of 

 life of mice in closed jars of about 2 liters' capacity and found as a 



