GENERAL PROPERTIES.' THE CORPUSCLES. 415 



has since been investigated with great care by a large number of 

 observers and under a great variety of conditions. The observation 

 has been abundantly confirmed, and indeed it would seem that the 

 reaction takes place very quickly. Within twenty-four hours, 

 according to some observers, and in less time, according to others 

 who have experimented during balloon ascensions (Gaule, Hallion, 

 and Tissot), the increase in* the number of corpuscles may be de- 

 tected, although the maximum increase comes on more gradually. 

 According to Kemp,* the number of blood plates is also greatly 

 increased by high altitudes, while the leucocytes are not affected. 

 There has, however, been much difference of opinion as to whether 

 this increase in number of the red corpuscles is relative or absolute, 

 that is, whether the total number of red corpuscles in the blood, 

 and therefore probably the total amount of hemoglobin, is increased, 

 or whether it is simply an apparent increase due, for instance, to a 

 diminution in the water of the blood and a consequent concentration 

 as regards the number of corpuscles, or to a variation in the distri- 

 bution of the corpuscles between the vessels of the skin and those 

 of the internal organs. The results published upon these questions 

 have been conflicting. One may, however, believe that the in- 

 creased number or concentration of red corpuscles is an adaptation 

 by means of which the oxygen-carrying capacity of the blood 

 is raised to compensate for the diminished amount of oxygen in the 

 air. According to one set of observers, this adaptation is brought 

 about by an absolute increase in the total number of red corpuscles, 

 and therefore in the total amount of hemoglobin. There seems 

 to be little doubt that such a change occurs in cases of long residence 

 in high altitudes, and we may assume that the diminished amount 

 of oxygen in the air or some other condition peculiar to these 

 altitudes acts as a stimulus to the blood-forming tissues (red mar- 

 row) and augments the output of corpuscles and hemoglobin. 

 Zuntz and his co-workers have shown in experiments upon dogs 

 that there is a visible increase in the red marrow of the bones as 

 a result of living for some months at a high altitude. According 

 to another set of observers, the adaptation is brought about by a 

 concentration of the blood. The blood-plasma is reduced in 

 quantity, perhaps by transudation of water into the tissues, and 

 therefore the number of red corpuscles and the amount of hemo- 

 globin become greater for each cubic millimeter. If we assume 

 that this smaller bulk of blood, more concentrated in corpuscles 

 and hemoglobin, circulates more rapidly, then also the oxygen- 

 carrying capacity of the blood is increased. In favor of this view, 

 Abderhalden, for instance, has claimed that, if animals of the 

 same species and same litter are bled to death and the total quan- 

 * Kemp, " American Journal of Physiology," 10, 34, 1904. 



