\/\.^ J- Lindhard. 



versa. When we take into consideration the different influence due 

 to the "dead space", when the frequency of respiration varies, the 

 series will appear much more characteristic, since the highest fre- 

 quency falls at the time of year when the total volume of air 

 respired is least. 



Two of the results apparently fall outside the series, the experi- 

 ments for November and January. In November the total volume 

 of air respired is just as great as in August, though both the alveolar 

 carbonic acid Pension and the frequency have increased as much as 

 could be expected according to the time of year. In January the 

 total volume of air respired is nearly as much as that for April, 

 and even when we remember that the frequency of respiration for 

 January is very high, this result will nevertheless appear remark- 

 able, especially in connection with the Copenhagen experiments. 



It has to be remembered here, however, that the November 

 experiments were made immediately after a fatiguing journey, which 

 means that the total capacity of the lungs was increased; but from 

 this it again follows, that the total volume of air respired must 

 remain large, if a given alveolar carbonic acid tension is to be 

 maintained. Lastly, it is not at all improbable that the after-effects 

 of this may still be felt in January. Jaquet and Stähelin^ have 

 experienced the after-effects from residence on a mountain for an 

 even longer time. 



The annual period appears most distinctly when we consider 

 the average depth of the single expiration, since, as mentioned, the 

 total volume of air respired and the frequency of the respirations 

 vary in an opposite direction. The two, otherwise well-separated 

 groups in the April experiments here fall together (with an average 

 respectively of 964 and 976), as the reduced total volume of air 

 respired owing to the cold is accompanied by a decreased frequency 

 of respiration. 



The volume of an expiration at 37° (saturated) is calculated in 

 the tables. 



The average values for these series may be given here. 



Vol. of an expiration 

 at 37°, (saturated) in cc. 



February 1909 918 ± 4-8, /^ = 23-5 



April 1907 (group II) 976 ± П'б, /^ = 455 



June 1907 1362 ± 106, fjt =- 565 



August — 1491 + 9-4, и = 43-3 



November — 1269 + 193, /u == 904 



January 1908 9135 + 122, /u = 625 



1 Arcliiv f. Exper. Pathologi u. Pharmacologi. Bd. 46, 1901; p. 300. 



