THE RED BLOOD CORPUSCLES 179 



number; namely, only 0.5 to 1.0 million per cubic millimeter. Their 

 number increases later on so that infants present higher values than 

 the average for adults. Pregnancy causes a slight increase and men- 

 struation a decrease. Physical exertion at low altitudes causes a con- 

 centration of the blood which Schneider and Havens 1 attribute to the 

 sudden passage into the blood of a large number of red corpuscles 

 which have been lying dormant in the body, chiefly in the splanchnic 

 area. Scott 2 believes this concentration to be effected by a passage 

 of fluid from the blood to the tissues, in consequence of the higher 

 blood-pressure coincident with muscular exercise. Massage, and 

 especially massage of the abdomen, produces a similar effect for the 

 same reason. During hibernation the number of the red corpuscles 

 is not materially changed. Neither is the specific gravity of the blood, 

 whereas the number of the white cells is decreased to about one-half 

 of normal. 3 



A very interesting phenomenon is the increase in the number of 

 the erythrocytes, resulting whenever high altitudes are attained. 

 Bert 4 and Viault, 5 who first studied this change, have found that the in- 

 habitants of low lands show this increase whenever they ascend a high 

 mountain and that persons permanently residing in a mountainous 

 country, constantly give counts above normal. It is then not unusual 

 to obtain increases to as much as 7,000,000 or 8,000,000 per cu. mm., 

 but in most cases the maximal value is not attained until about twenty- 

 four hours have been spent at the high altitude. According to Kemp, 8 

 the number of the platelets is also increased, but the leukocyte count 

 remains the same. 



Two possibilities present themselves, namely, it is conceivable 

 that this increase is dependent upon a greater formation of red cells 

 by the hematopoietic tissues or secondly, that it is due to changes in 

 the quantity of the blood plasma. The second view, originally ex- 

 pressed by Grawitz, 7 embodies the possibility that the sojourn in 

 mountainous regions leads to a concentration of the blood, because 

 the greater respiratory activity coincident with muscular exertion and 

 sweating, occasions a loss of a considerable quantity of water. 

 Gaule, Hallion and Tissot, however, have shown that an increase in 

 the number of the red cells also appears during balloon ascensions, 

 and hence, muscular efforts cannot be considered as the cause of this 

 phenomenon. Abderhalden 8 and Bunge, 9 who also believe that the 

 increase is only an apparent one, assert that the blood is really made 



i'Am. Jour, of Physiol., xxxvi, 1905, 239. 



2 Ibid., xliv, 1917, 298. 



3 Rasmussen, Ibid., xli, 1916, 465. 



4 La pression barom6trique, Paris, 1878, or Compt. rend., xciv, 1882, 805. 

 5 Compt. rend., cxi, 1890, 917. 



6 Am. Jour, of Physiol., x, 1904, 34. 



7 Berliner klin. Wochenschr., xxxii, 1895, 743. 



8 Zeitschr. fur Biol., xliii, 1902, 423. 



9 Verhandl. des Kongr. f. innere Med., xiii, 1895, 192. 



