36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 60 



the animal in cage 4 remained alive, while the one in cage 3 was the 

 first to die. They concluded that the deaths were due to a volatile 

 poison which was absorbed by H 2 S0 4 . 



Such were their statements, definite and precise and apparently 

 backed up by well-contrived experiments. 



As it turns out, no one except Merkel has claimed to have obtained 

 similar results. 



Haldane and Lorrain Smith constructed an air-tight wooden 

 chamber containing 70 cu. ft., measuring 6 ft. 2 in. by 2 f t. 1 1 in. 

 by 3 ft. 1 1 in., and fitted with a large window. One of them stayed 

 4 hours within the chamber with no renewal of the air until the 

 C0 2 reached 3.9 per cent. The subject had slight hyperpncea and 

 slight headache. Both disappeared as soon as he left the chamber. 

 In another experiment they varied the conditions by placing a large 

 tray of soda lime in the roof of the chamber. There were very 

 much less hyperpncea and no headache on this occasion. Slight 

 hyperpncea occurred when the deficiency of oxygen in the cham- 

 ber air became greater than 5.5 per cent. In yet another ex- 

 periment they charged the air of the chamber with 5.4 per cent 

 C0 2 at the beginning, and at the same time kept the oxygen per- 

 centage up to 19.8 per cent. There was great hyperpncea, with 

 great relief on coming out, but frontal headache followed the experi- 

 ment. In other experiments they breathed the same air over and 

 over again, in and out of a bag ; they found the distress became un- 

 bearable when the CO, reached 10 per cent. On breathing 5 per 

 cent of COo, hyperpncea and headache occurred equally whether 

 there was 14 per cent or 70 per cent of oxygen in the bag, so they 

 concluded that with air vitiated by respiration up to the extreme 

 limit which we can tolerate, the diminution in the percentage of O, 

 is practically without effect on the hyperpncea. Brown-Sequard 

 and D'Arsonval stated that they had breathed air containing 20 per 

 cent of pure C0 2 for 2 hours without hurt and with no marked dis- 

 tress, and drew a distinction between the chemically pure CO, and 

 impure exhaled C0 2 . This is a wholly erroneous statement. 

 Haldane and Lorrain Smith breathed air containing 18.6 per cent 

 pure CO,. After 15 seconds there was hyperpncea; in 60 seconds 

 this was severe ; at the end of 90 seconds the subject turned blue and 

 had to stop; in the 134th second the hyperpncea ceased. They next 

 breathed in and out of the bag of air through a Woulfe bottle con- 

 taining soda lime. The subject stopped after 2 hours because he 

 was getting blue in the face and felt abnormal. There was no 



