RESUME. 



Т 



he contents of the preceding pages may be summarized under 



the following heads. 



I. In Arctic regions there is a distinct annual period in the 

 respiration with turning-points at the end of the summer and the 

 end of the winter. 



For the functions investigated : respiration-frequency, total vol- 

 ume of air respired, alveolar carbonic acid tension and metabolism, 

 the changes from February to August are as follows, taking the 

 control experiments as the starting-point. 



The respiration-frequency decreases by 165 *^/o 



the alveolar CO, tension decreases by 2Г9°/о 



the total volume of air respired increases by 35*7 ^/o 



the respiratory metabolism increases by 242 ^lo 



The periodicity is due first and foremost to the variations in 

 the intensity of the sunlight. 



II. The respiration characteristic for the Arctic summer is even 

 in details the same as has been found in experiments during rest 

 in the High Alps. 



It is therefore extremely probable, that this last is likewise due' 

 to the sunlight, and not, as hitherto supposed, to low air-pressure 

 and presumed lack of oxygen. 



III. Experiments made at low temperatures show a peculiar 

 change in the respiration suggestive of the respiration during hiber- 

 nation. 



IV. The opinion expressed by Haldane and Priestley, that 

 the alveolar carbonic acid tension is a constant magnitude for each 

 individual, and that the total volume of air respired is so regulated 

 that the status quo is maintained in this regard, is in all probability 

 unmaintainable. 



