Summary and Discussion 499 



which one may assume that the differences will be very slight, 

 it is indispensable to observe scrupulously both chemical precision 

 and above all physiological exactness. 



It is not the first one of these conditions which is missing, at 

 least apparently, in the work of Vivenot. If we may believe his 

 figures, the analysis he made of the carbonic acid contained in one 

 expiration was exact down to the sixth decimal, and that by itself, 

 I confess, would be enough to make me distrustful. Thus the 

 quantity of carbonic acid exhaled in 24 hours at normal pressure 

 being 1300.37760 gm., in compressed air it would be 1449.49350 gm. 

 That seems very conclusive. But how were these figures obtained? 

 By analyzing the product of one expiration "as strong as possible, 

 but made without great efforts" at normal pressure, which gave 

 0.2176 gm. of carbonic acid, and of one expiration under compres- 

 sion, which gave 0.2676 gm.; by taking into account the average 

 number of respiratory movements per minute, which was 4.15 for 

 the first case and 3.76 for the second; and finally, by multiplying 

 the number thus found by 60 then by 24. 



As for me, I refuse to grant any sort of value to figures ob- 

 tained by a method so absolutely contrary to what true precision, 

 physiological precision, requires. To take as a basis one expira- 

 tion, made at the rate of 3.76 respiratory movements per minute, 

 certainly extraordinary conditions, is to expose oneself in the name 

 of the experimental method to the severest criticisms. I do not 

 hesitate to say, without going into the details of the experiments, 

 without laying stress on the "rubber tubes not hermetically closed" 

 (page 470) , that all this part of Vivenot's work, in spite of his in- 

 numerable tabelles and his columns of figures in which the table 

 of logarithms has "worked wonders," should be considered null 

 and void. 



This is also the opinion of Panum, who studied the same ques- 

 tion, under conditions which are better, no doubt, but are still open 

 to reproach. However, his experiments give evidence in the same 

 direction, and tend to show that in compressed air there is more 

 carbonic acid produced in a given time than at normal pressure. 



I admit that to my mind this fact is not proved; a glance at the 

 table published by Panum is enough to justify my doubts even 

 about the results of his experiments; for we see that after all there 

 are only four of them which are comparable and under normal 

 conditions, and that of these four only one was made at ordinary 

 pressure. Moreover, the respiration was carried on for only 10 



