INCREASE OF BLOOD CORPUSCLES 601 



arrange the observation material, as a preliminary to elim- 

 inate all the factors connected with fatigue, cardiac over- 

 exertion, and the like. The amount of influence of climatic 

 factors was, however, necessarily to be included in the study. 



Influence of Climatic Factors. In the first place the 

 effects of cold, which is very appreciable at great heights, 

 are to be thought of; but it should be remembered that the 

 maintenance metabolism in Greenland was not found any 

 greater than in the tropics and that, as Durig remarks, ' ' the 

 vital flame does not burn any more briskly under the in- 

 fluence of cold than in the sun-browned Indians. ' ' A number 

 of other climatic factors, as the wind, rarefaction, the ioniza- 

 tion and electrical potentials of the atmosphere have no 

 more definite effect upon metabolism, as far as can be recog- 

 nized. Therefore the fall in oxygen pressure necessarily 

 must be regarded as the most important item for consi- 

 deration. 54 



Increase of Blood Corpuscles. One of the most striking 

 alterations developing in elevated climatic conditions is the 

 increase in the number of red blood corpuscles in the unit 

 of volume of a sample of withdrawn blood. At present the 

 majority of writers incline to the assumption that this is not 

 an actual increase, but that, as Zuntz believes, either the 

 distribution of the corpuscles is so altered that a larger 

 proportion of them are accumulated in the dilated dermal 

 capillaries, or on the other hand there exists a concentra- 

 tion of the blood as the result of a passage of fluid from the 

 vessels (which might be thought of as connected in the first 

 place with an increased evaporation or in the second place 

 with a process of forcing the plasma out from the action 

 of vasomotor factors). That rapidly developed, transitory 

 changes of the blood, such as for example have been ob- 

 served inside of an hour in a balloon ascension, may reason- 

 ably be related with causes of such a character, can scarcely 

 be doubted. That a more protracted sojourn on mountain 



M Cf. A. Lowy, Deutsche Med. Wochenschr., 1904, 121. 



