Contribution to tiie Physiology of Respiration under tlie Arctic Climate. 167 



22/3 which gave 10,644 gr. CO, and one for ^»/g ^ith 11,713; this 

 does not suggest less metabolism in the summer. 



If we exclude April and May, which fall quite outside the rest 

 of the series, we find that the frequency varies in the same direction 

 as in my experiments: the summer and autumn have slightly lower 

 values than the winter and spring. The difference is however only 

 7 — 7o '^/o, not the 32 "/o given in his paper. 



Similar conditions seem to prevail in the case of the amount of 

 carbonic acid given off; but here, as mentioned, we lack information 

 regarding the food and body weight, quite apart from the fact, that 

 the numbers are more or less affected by errors arising from un- 

 controlled muscular movements. 



For the rest, the author mentions, that the carbonic acid curve 

 is symmetrical with the curve for the air temperature, which further 

 shows, according to the above-cited investigations of Johansson and 

 others, that he had not maintained the necessar}^ tranquillity during 

 the experiments. 



The author is of a similar opinion with regard to the relation 

 between the production of carbonic acid and the air-pressure. None 

 of these factors can in his opinion, however, be the cause of the 

 annual period. He mentions the light as a possibility. 



Altogether, it seems to me that the conclusions E. Smith has 

 drawn from his material are not justified, as also that this material 

 is on the whole not suited to form a basis for conclusions with 

 regard to the annual periodicity of the respiration. 



