138 J- Lindhard. 



on Monte Rosa? Zuntz and Loewy give an oxygen tension of 536 

 mm. for the Alpine guide Bianclietti and add, that he was thus not 

 more favourably placed than any of the others. But Loewy has 

 himself shown ^, that an oxygen tension of 40 — 45 mm. would be 

 sufficient. This does not point to the lack of oxygen as the cause 

 of the hyperpnoë. 



Galeotti^ has now shown, that there is a reduction in the 

 alkalinity of the blood by 36—47 ^Vo on Monte Rosa, and this may 

 explain the hyperpnoë. But is the reduced oxygen tension the cause 

 of the reduced alkalinity of the blood? It may be so under certain 

 circumstances; but on Monte Rosa it seems to me from what has 

 been shown above that there is some doubt about the matter. 



Whilst the variations in the temperature and air-pressure in my 

 experiments have on the whole only slight influence on the alveolar 

 carbonic acid tension, the latter for other reasons is subject to con- 

 siderable fluctuations in the course of the year. 



Omitting all the experiments with undoubted increase in the 

 carbonic acid tension owing to the effect of cold, we obtain the, 

 following series: 



COg in mm. of Hg 



Copenhagen, February 09 342 4: 012, ц = 059 

 "Danmark's Harbour", 



(76° 46' N.) April 07 30-6 ± 029, ß = Г 14 (group II) 



— — June 07 29-4 +. 024, fj. =- 1-22 



— — August 07 26-7 ± 0-27, ц = 105 (exp. 66 



— — November 07 296 ± 038, ^ = 180 omitted) 



— — January 08 318 ± 022, // = 112 



There are two things we notice here: the annual period with a 

 maximum in January, minimum in August, and the obvious fact, 

 that the carbonic acid tension in the Greenland experiments, even 

 at its maximum value, is lower than in the Copenhagen experiments. 



If we undertook a spring and summer voyage from Copenhagen 

 to North-East-Greenland, we should undoubtedly obtain a series of 

 values for the alveolar carbonic acid tension, which would corre- 

 spond to the first four values in the above series; we are therefore 

 entitled to use the control experiments as the starting-point, in order 

 in the end to seek for an explanation, why the January experiments 

 show lower values for the carbonic acid tension than these. 



As already mentioned, it is very improbable that the annual 

 period stands in any connection with the temperature conditions, 



1 Pflügers Archiv. Bd. 58, p. 409, 1894. 

 ^ cit. Höhenkl. u. Bergw. Kap. X. 



