Contribution to the Phj^siologj' of Respiration under the Arctic CHmate. 161 



from one another. TIGERSTEDT^ has also maintained, that in the 

 same individual under the same outer conditions the amount of 

 carbonic acid given off only varies slightly from day to day, even 

 for months. 



It will be seen that there is a distinct rise after the meals and 

 then the metabolism sinks again regularly towards the value given 

 in the morning experiments at the corresponding time of year. 



The morning experiments in May are however, like the "cold 

 experiments", under the value which corresponds to the time of 

 year, and several of the day-experiments for May are probably in- 

 fluenced by the relatively low temperature. 



The Annual Period. 



As result of the foregoing it may be said, that there is a dis- 

 tinct annual fluctuation in the respiratory functions in the Arctic 

 regions. The turning-points of the curve lie towards the end of the 

 summer, presumably at the time when the sun "begins to go down", 

 and in the beginning of spring, probably shortly after the sun has 

 again appeared above the horizon. Considering the changes from 

 winter to summer, we see that 



the respiration-frequency 



the alveolar carbonic acid tension 



the total volume of air respired 



the respiratory metabolism 



Excluding experiment No. 102 of the January series the decrease 

 in the respiration-frequency becomes 316"/o. 



When we remember that in January there may still be some 

 after-effects from the journey in autumn, especially as regards the 

 total volume of air respired, as also that January is probably not 

 the month for the turning-point of the curve but that this falls a 

 month later, then it is probable, that the results given here are less 

 than the annual variation will prove to be on further investigation. 



Taking the control-experiments as starting-point and remembering 

 that special conditions have prevailed during my January experi- 

 ments, we may imagine a journey beginning in Copenhagen in Fe- 

 bruary and ending in North-East Greenland in August; we then 

 obtain the following results: 



The respiration-frequency 

 the alveolar carbonic acid tension 

 the total volume of air respired 

 the respiratory metabolism 



decreases by 32-4 ^'/o 

 decreases by 160 "/o 

 increases by 10*4 "/o 

 increases bv 15"9 ^*/o 



decreases by 16*5"/o 



decreases by 21*9 "^/o 



increases by 35*7 ^/o 



increases by 242 ^lo 



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