RED CORPUSCLE CONTENT OF THE CIRCULATING BLOOD 



569 



Stead and Ebert (1941) avIio recently carried out such bleeding 

 experiments found that, in normal human subjects, 72 hours after 

 venesection, the red corpuscle volume always appears lower than the red 

 corpuscle volume predicted from the pre-haemorrhage red corpuscle 

 volume and the volume of red corpuscles removed. The changes in hema- 

 tocrit reading are, however, relatively small. Later, Stead and Ebert 

 experimented with dogs in which a marked drop in hematocrit reading 

 was produced by massive bleeding. Tlu^ spleens were removed as, under 

 certain conditions, the spleens of dogs discharge blood rich in corpuscles 

 into the circulation. In experiments in which aljout half of the red cor- 

 puscles were removed, it was found that, while from the hematocrit 

 reading and the plasma volume a red corpuscle volume of 1 390 cm^ was 

 calculated, the volume of red corpuscles removed, plus the red corpuscle 

 volume after bleeding, constituted 1039 cm^, only. From this result, 

 these experimenters conclude that, when the hematocrit reading is 

 approximately 50, the red corpuscle volume calculated from the plasma 

 volume and the hematocrit reading is approximately 25 per cent higher 

 than the true red corpuscle volume. 



Table 6. — Coepttscle Content Obtained when Using 

 Different Methods 



Mean value of those cases in which all three methods were applied : 

 2830 I 2320 I 1990 



