Contribution to the Physiology of Respiration under the Arctic Climate. 157 



creased total volume of air respired in "the light-experiments", this 

 must certainly be due to purely psychical factors. 



It appears, therefore, that light is not credited with much, and 

 yet, when we consider my Greenland experiments, this must be the 

 main thing. On this point I am again in agreement with Hassel- 

 balch's experimental investigations. He found, both in himself and 

 in Dr. J., an increase in metabolism of ca. 5 ^lo in the morning after 

 a light-bath. The effect w^as of short duration, but the time of ex- 

 posure was only 1 hour. It is not a contradiction, that a less 

 powerful but longer exposure can give both a stronger and more 

 lasting result. 



Although ZuNTz and Loewy, as mentioned, do not attach very 

 much importance to the light, there are various things in their 

 work, which point in the same direction as the series noted as ana- 

 logous to my experiments. Thus, with regard to the effect on the 

 metabolism, there is constantlv a recognizable relation to the time. 



259-2 aver, of 16 experiments in bed 

 2720 aver, of 5 experiments on the train 



The last is of less importance; but it is included just to show 

 that the light plays a small part — if any at all : 



In bed ^'/8 267-3 

 — ^/9 272-9 



thus, again a rise on the last day; on the train, same day, 272-0. 



It seems to me that Zuntz and Loewy have in some way mis- 

 understood their problem with regard to the investigations on the 

 effect of light. The light is a climatic factor in the mountains as 

 in the Arctic climate, and its influence cannot therefore be studied 

 by making experiments in the sun and in the shade on the same 

 day and at the same place. If we shorten the time of the experi- 

 ment we must to the same extent strengthen the excitation, if we 

 Avish to obtain an appreciable result. When we desire to have a 

 strong, momentary effect of light, we must, as Hasselbalch has 



1 Höhenklima u. Bergwanderungen. Chap. VIII. 



12* 



