Contribution to the Physiologj' of Respiration under tlie Arctic Climate 159 



pause and effect. Detailed investigations of Tigerstedt and Sonden^ 

 have given the result, that the variations in the temperature of the 

 body are probably entirely determined by the fluctuations of the 

 metabolism. And my experiments at different times of the day 

 point quite in the same direction. A decrease in the metabolism 

 under the cold, as in poikilotherms or in hibernating animals in 

 winter, is thus not proved, as far as is known to me. My "cold 

 experiments" mentioned above point however in this direction. 



As already shown, the April experiments may be divided into 

 two well-separated groups according to the air-temperature: 



Air-temperature ? ., ., , 



•^ cc. per kilo, ix liour 



group I 6°-3 с 201 + 0-95, n --= 316 



group II 110 - 214 4; 0-67, fjL -^ 2-45 



So far as known to me, there is no other difference whatsoever 

 in the experimental conditions for these two groups than the different 

 outer temperatures; but on the other hand, the difference in this 

 regard is distinct. The morning experiments of May join on to the 

 first of these groups. 



Air-temperature ^i -i «> i 



' cc. per kilo. & per hour. 



7°-6 С 203 a = 1-4 



The temperature was read from the gas-meter; the air surroun- 

 ding my body during the experiments was considerably colder, 

 especiallj^ in the April experiments. I felt the cold, often a great 

 deal, but without real discomfort, and I did not react with chattering 

 or muscular movement of any kind. There might have been an 

 inconsiderable muscular stiffness in the lower limbs when I rose up 

 after the experiment; but I am unaware of any appreciable difference 

 between these and the other days of the experiments. And the ex- 

 periments, as mentioned, were not planned with this object in view, 

 to investigate the effect of the low temperature. 



Whilst there is a decreasing effect on the total volume of air 

 respired and the frequency, as also most probably on the alveolar 

 carbonic acid tension, on the 4 or 5^ successive "cold days" in 

 April, such a progressive "adaptation" cannot be detected in the 

 metabolism; on the contrary, there is here such a marked parallel- 

 ism with the temperature that it appears more than a mere chance. 



1 Skandinav. Archiv, f. Ph3'siologie. 6, 1895. 



- Experiment No. 34, where the gas-analysis is wanting, is also included so far 

 as regards the frequency and the total volume of air respired. 



