VARIATIONS IN THE NUMBER OF RED-CORPUSCLES. 341 



ished destruction of the blood-corpuscles. A relative increase may be 

 brought about in different ways. For example, another division of the 

 blood-corpuscles in the vascular system has been supposed, whereby 

 the blood-corpuscles accumulate in the capillaries, from which region 

 the blood has been examined most often (ZUNTZ). It is also claimed 

 that a concentration of the blood takes place by increased evaporation 

 (GRAWITZ), and finally an increase in the blood-corpuscles has also been 

 explained by assuming a contraction of the vascular system with the 

 pressing out of plasma (BUNGE, ABDERHALDEN *). In connection with 

 these experiments, it must be remarked that several trustworthy observa- 

 tions show that under the influence of diminished blood-pressure an 

 actual increase in the red blood-corpuscles takes place. These and 

 especially those of ZUNTZ and his co-workers have shown that under 

 these conditions an increased activity occurs in the red bone-marrow. 

 This question is still not clear. COHNHEIM and collaborators 2 have 

 observed in man and dogs, that no essential increase in the blood-corpuscles 

 and haemoglobin occurs in high altitudes after 12 days. They do not 

 dispute the action of a continued residence in high altitudes, and they also 

 do not dispute such an action upon rabbits and mice. They explain 

 this in these animals by a concentration of the blood due to a loss of water 

 which is not replaced. In man and dogs on the contrary the loss of 

 water brought about by perspiration is immediately replaced and the 

 concentration of the blood prevented and the increase in the number 

 of blood-corpuscles and of haemoglobin is not observed. 



A decrease in the number of red corpuscles occurs in anaemia from differ- 

 ent causes. Every excessive hemorrhage causes an acute anaemia, or, more 

 correctly, oligaemia. Even during the hemorrhage, the remaining blood 

 becomes by diminished secretion and excretion, as also by an abundant 

 absorption of parenchymous fluid, richer in water, somewhat poorer in 

 proteins, and strikingly poorer in red blood-corpuscles. The oligaemia 

 soon passes into an hydraemia. The amount of protein then gradually 

 increases again; but the re-formation of the red blood-corpuscles is slower, 

 and after the hydraemia follows also an oligocythaemia. After a little 

 time the number of blood-corpuscles rises to normal. INAGAKI S has 

 made thorough investigations on the changes which the number, volume 

 and haemoglobin content of the erythrocytes undergo after drawing blood 

 as well as during regeneration. It is impossible here to enter more in 



1 The literature on this subject may be found in Abderhalden, Zeitschr. f. Biologic, 

 43; van Voornveld, Pfliiger's Arch., 92. 



2 Hohenklima und Bergwanderungen, by N. Zuntz, A. Loewy, Franz Miiller, and 

 W. Caspari, Berlin, 1906; Otto Cohnheim, G. Kreglinger, L. Tobler, O. H. Weber, 

 Zeitschr. f. physiol. Chem., 78 and Cohnheim, Ergebn. d. Physiologic, 1912, 12. 



3 Zeitschr. f. Biol., 49. 



