Theories and Experiments 471 



So it is proved, in the opinion of Vivenot, that in one expiration 

 there is more carbonic acid in compressed air than at normal pres- 

 sure. But on the other hand, the respiratory capacity is greater 

 in the first case than in the second. Is there a proportion between 

 these two increases, and can one perhaps be considered as the 

 result of the other? Vivenot replies to this question as follows: 



If we compare the proportions of the quantities of carbonic acid 

 exhaled under normal pressure and in compressed air and the respec- 

 tive proportions of increase of the pulmonary capacity, we find: 



Respiratory capacity Quantities of carbonic acid 



I produced 



I In normal I In com- I In normal | In compressed 



air I pressed airl air air 



In myself | 3425 cc. | 3533 cc. 



In Dr. Lange | 3950 cc. | 4083 cc 



0.2176 gm. 

 0.2505 gm. 



0.2676 gm. 

 0.2959 gm. 



On the average j 3687.5 cc. [ 3809.5 cc. j 0.23410 gm. | 0.28175 



An increase of 1 122.0 cc. j 0.04765 gm. 



Or, representing b y 1 the values corresponding to normal proportions 



I 1 



In myself 

 In Dr. Lange 



1 : 1 + 



31.7 



1 + 



4.35 



1 I 1 



1 : 1+ I 1 : H 



29.7 I . 5.53 



111 1 



On the average „_ 1 : 1H 1 : 1 + 



| 30.80 j 4^91 



So, while the increase of the pulmonary capacity in compressed 

 air rises to 1/30.80, the quantity of carbonic acid exhaled has risen 

 1/4.91. The ratio of the increases is therefore about 1:6. If I calcu- 

 late what the quantity of carbonic acid exhaled would be, if the 

 increase observed in the compressed air was proportional to the 

 increase of the pulmonary capacity, I find the proportion 3687.5 cc: 

 3809.5 cc. = 0.23410 gm. : x, hence x = 0.24197 gm. The increase cal- 

 culated in this case is 0.00787 instead of 0.04765 gm. which the experi- 

 ment gives. 



This considerable difference between the calculation and the 

 experiment shows clearly that the increase in the quantity of carbonic 

 acid exhaled in compressed air is not proportional to the increase in 

 pulmonary capacity, which can have only a small share in causing this 

 increase. It would therefore seem permissible to state that the increase 

 in the quantity of carbonic acid exhaled would be produced by the 

 compression itself, acting partly according to Dalton's Law and caus- 

 ing a greater absorption of oxygen, under the direct influence of the 

 compression on the one hand, and of the fact that the compressed air 

 itself contains 3/7 more oxygen in the same volume. 



A calculation still had to be made of the total increase in the 

 carbonic acid produced in a given time. To do this, Vivenot in his 

 calculation takes into account both the number of respirations 



