472 



Historical 



which he makes in one minute, and the quantity of carbonic acid 

 contained in one expiration. He explains his method of procedure 

 as follows: 



The air exhaled by myself in one expiration contained, as was 

 said above, 0.2176 grams under normal pressure, and 0.2676 grams of 

 carbonic acid in compressed air. Now since at the time when the 

 analyses were made (from August 26 to September 13) the average 

 of my respirations was 4.15 in normal air and 3.76 per minute in 

 compressed air, we can draw the following conclusion from this series 

 of experiments: 



Quantity of carbonic 



acid exhaled, expressed 



in grams 



Quantity of carbon 

 consumed, expressed 

 in grams 



I Normal | Compressed I Normal | Compressed 

 I pressure | Air pressure air 



In one minute 

 In one hour __ 

 In 24 hours __ 



0.903040 | 1.006176 | 



54.18240 | 60.37086 | 



1300.37760 | 1449.49350 I 



0.24628 | 0.27441 



14.7770 | 16.4647 



354.6480 | 395.1528 



If we compare the figures obtained for normal air with those 

 given by the most trustworthy authors, we find that the quantity of 

 carbonic acid exhaled in one hour by persons from 20 to 28 years old 

 has been estimated by Andral and Gavarret at 44.55 grams on 

 the average and at 51.7 grams at the maximum, and by Valentin on 

 the average at 39.146. Reduced to carbon, these figures, in the calcu- 

 lation of Andral and Gavarret, correspond to an average quantity per 

 hour of 14.1 grams, and in that of Valentin, to 10.665 grams. Dumas 

 specifies 10 grams as being the probable average consumption of 

 carbon per hour, and 15 grams for men of exceptional strength. 



We see by this that figures obtained for myself at normal pressure, 

 although my constitution is not very robust, correspond to the highest 

 figures obtained by the authors, but that the results obtained in com- 

 pressed air still exceed these quantities considerably. The calculation 

 made for a stay of twenty-four hours in compressed air gives only an 

 ideal result, because the stay in reality lasted only two hours per day, 

 and therefore in this case one should take only the results of com- 

 pressed air for two hours and add to them those of normal air for the 

 22 hours remaining. When we make the calculation in this way, we 

 find as the real quantity of carbonic acid exhaled in 24 hours, after a 

 daily treatment of two hours in compressed air, 1312.7539 grams, and 

 as the corresponding quantity of carbon consumed during the same 

 time 358.0234 grams. Whence it follows that even after this reduction 

 the production of carbonic acid found by me still considerably exceeds 

 that found by other observers under normal conditions. 



The explanation of the high figures which I obtained at norm.al 

 pressure lies in the fact that the analyses of the expired air could not 

 be made at the time of the first treatments for lack of suitable appara- 

 tuses and reagents, and were made only after I had already taken 

 more than a hundred treatments in compressed air. Whence it follows 

 that in the figures obtained upon myself at normal pressure the effect 

 of a prolonged use of compressed air is already a factor, that is, an 



