572 ADVENTURES IN RADIOISOTOPE RESEARCH 



volume and the hematocrit figure, the corpuscle content determined by 

 the radio-iron method being 77 per cent of that calculated when applying 

 the plasma (dye) and the hematocrit values. This is a result similar to 

 that obtained by us when using the ^^P method. 



Summary 



To a blood sample taken from a human subject, a minute amount of sodium 

 phosphate containing the radioactive phosphorus isotope ^^p is added. Then, the 

 sample is shaken in a thermostat for two hours at 37° C. A part of the blood sample 

 thus containing labelled corpuscles is reintroduced into the circulation. After the 

 lapse of about 5 minutes, a blood sample is secured and the radioactivity of the 

 corpuscles of this sample is compared with the radioactivity of the reintroduced 

 corpuscles of equal weight. The ratio of the radioactivity of the two samples 

 is a measure of the amount of corpuscles present in the circulation. 



The mean value of the corpuscle content of the lean human subjects investi- 

 gated was found to be 36.0 gm per kgm body weight. 



In a number of cases, the plasma volume was determined by means of the dye 

 method and the corpuscle content of the circulating blood was calculated from 

 the plasma volume and the hematocrit figure. The figures obtained in this way, 

 were about 18 per cent higher than those found for the corpuscle content deter- 

 mined according to the ^^P method. 



When adding to the plasma volume determined with appHcation of the dye 

 method, the corpuscle volume found by means of the ^^p method, we obtain the 

 blood volume. The value thus calculated is independent of the hematocrit figure. 

 The values obtained by means of this direct method of determination of the blood 

 volume are found to be about 9 per cent smaller than the values calculated from 

 the plasma (dye) volume and the hematocrit figure. 



The difference between the determined and the calculated corpuscle content 

 (making use of the hematocrit figure) respectively between the determined and 

 the calculated blood volume, supports the conclusion drawn by Whipple and 

 his colleagues that the hematocrit figure is no proper representative of the corpuscle 

 content of the circulating blood, this content being smaller than the hematocrit 

 figure. This conclusion is based on the assumption that the dye method supplies 

 us with a correct value for the total plasma volume. 



Literature 



E. AsMussEN (1942) Acta Physiol. Scand. 3, 156. 



E. L. Gabdozo (1941) Arch. need. Physiol. 25, 410. 



I. G. Gibson Jr. and K. A. Evelyn (1938) J. Clin. Inv. 17, 153. 



L. Hahn and G. Hevesy (1940) Acta Physiol. Scand. 1, 3. 



L. Hahn and G. Hevesy (1942) Acta Physiol. Scand. 4, 376. 



P. F. Hahn, W. M. Balfour, J. F. Ross, W. F. Bale and G. H. Wipple (1940) 



Science 93, 87. 

 C. W. Hooper, F. P. Smith and G. H. Whipple (1920) Amer. J. Physiol. 51, 



205. 



F. P. Smith, H. R. Arnold and G. H. Whipple (1921) Amei-. J. Physiol. 56, 

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E. A. Stead and R. W. Ebert (1941) Amer. J. Phijsiol. 132, 411. 

 R. Wennesland (1940) Acta Physiol. Scand. 1, 49. 



