NUMBER OF RED CORPUSCLES. 323 



in the capillaries, from which region the blood lias 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 contrac- 

 tion of the vascular system with the pressing out of plasma (BuNGE, 

 ABDERHALDEN l ). In connection with these experiments, it must be 

 remarked that several trustworthy observations show that under the 

 influence of diminished blood-pressure an actual increase in the red 

 blood-corpuscles takes place, and ZUNTZ 2 and his co-workers have also 

 shown that the activity in the red bone-marrow is increased. 



A decrease in the number of red corpuscles occurs in anemia 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 a hydraemia. The amount of protein then 

 gradually increases again ; but the reformation of the red blood-corpuscles 

 is slower, and after the hydraemia follows also an oligocythsemia. After 

 a little time the number of blood-corpuscles rises to normal. INAGAKI 3 

 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 detail as to the results, but simply to state that they 

 substantiate the previously known observation that during regenera- 

 tion irregularities may occur in the relation between the quantity of 

 hemoglobin and the number of erythrocytes. This he explains by the 

 fact, as claimed by BOHR (see page 271), that there exist different 

 haemoglobins containing different quantities of iron. A considerable 

 decrease in the number of red corpuscles also occurs in chronic anaemia 

 and chlorosis; still in such cases an essential decrease in the amount of 

 haemoglobin occurs without an essential decrease in the number of blood- 

 corpuscles. The decrease in the amount of haemoglobin is more character- 

 istic of chlorosis than a decrease in the number of red corpuscles. The 

 opinions on the changes in the blood in anaemia and chlorosis differ 

 very considerably. 4 



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. 



3 Zeitschr. f. Biol., 49. 



4 Complete analyses of chlorotic blood may be found in Erben, Zeitschr. f. klin. 

 Med., 47. 



