Contribution to the Physiology of Respiration under the Arctic Climate. 131 



They found inter alia, that a quiet, regular respiration could be 

 produced by varying the composition of the inspired air. 



In sharp contrast to the standpoint taken up by the authors men- 

 tioned, we have a series of investigations by Zuntz, Loewy and others Ч 



The German investigators maintain, that whilst the oxygen ten- 

 sion in the alveolar air regularly falls with the air-pressure, this is 

 not the case with the carbonic acid tension, which inter alia is 

 likewise dependent on the total volume of air respired. When the 

 latter is increased, owing to the lack of oxygen, the alveolar car- 

 bonic acid is reduced secondarily; similarly, the carbonic acid ten- 

 sion is reduced in the blood when lactic acid is formed. For these 

 two reasons we should as a rule expect reduced carbonic acid ten- 

 sion at high elevations. If the fall in the carbonic acid were pri- 

 mary, we should expect a reduced total volume of air respired; 

 since the oprposite is the case, it must be because the sum of the 

 excitements ("Reize"), which are characteristic for the mountain 

 climate, has been increased; we cannot imagine, namely, that the 

 centre alters its excitability. As a rule it is certainly the carbonic 

 acid tension which determines the volume of air respired; but it 

 might well be imagined, that vicarious excitements arose under the 

 special climatic conditions. The authors would not have found it 

 necessary to refer to the alveolar carbonic acid tension had it not 

 been that Mosso had put forward his akapnia as the cause of 

 mountain-sickness'^. It may well be admitted now, that these two 

 phenomena have nothing Avhatsoever to do with one another; since 

 it was just in the two members of the German Expedition who 

 suffered from mountain sickness, that no fall occurred in the car- 

 bonic acid tension, though the latter was found very distinctly in 

 all the other members. 



For comparison with the above-cited values of Ward I may 

 give here two series from the results of the German Expedition. 



N. Zuntz (1895) 



N. Zuntz (1901) 



> Zuntz, Loewy, Müller, Gaspari: Höhenklima und Bergwanderungen in ihrer 



Wirkung auf den Menschen. Berlin 1906. 

 - Mosso: Der Mensch auf den Hochalpen. Leipzig 1899. 



