Originalh- communicated in Acta Physiol. Scand. 4, 375 (1942). 



52. DETERMINATION OF THE RED 

 CORPUSCLE CONTENT 



G. Hevesy and K. Zerahn 



From the Institute of Theoretical Physics, University of Copenhagen 



Some time ago, a method of determination of the red corpuscle content 

 was described (Hahn and Hevesy, 1940). Corpuscles containing label- 

 led phosphorus compounds are introduced into the circulation of the 

 rabbit, for example, and the labelled phosphatide content, or the 

 labelled acid- soluble phosphorus content of the corpuscles of samples, 

 secured after the lapse of few minutes, is compared with the correspond- 

 ing content of the corpuscles injected. Such a comparison indicates 

 to what extent the labelled corpuscles introduced into the circulation 

 are diluted by the corpuscles of the circulation, and it permits thus 

 the calculation of the red corpuscle volume of the rabbit. 



In the present note, a simplified form of the above mentioned method 

 is described. The modified method is based on the comparison of the 

 total labelled phosphorus content of the corpuscles injected, with the 

 total labelled phosphorus content of the corpuscles secured after the 

 injection took place. The corpuscles are labelled in vitro. A blood sample 

 of the rabbit is shaken in the thermostat for 1 to 2 hours in the presence 

 of labelled sodium phosphate. By this procedure the corpuscles get 

 labelled. The blood containing the labelled corpuscles is then reintroduced 

 into the circulation of the rabbit. This modification of the previously 

 described procedure was worked out in view of a possible clinical appli- 

 cation of the method. 



LABELLING OF THE CORPUSCLES 



About 20 cm^ of blood are removed from the rabbit, placed in a flask the walls 

 of which are coated with paraffin, labelled phosphate of neghgible weight (see 

 below) is added, and the bipod is gently shaken in a thermostat for 2 houis at 

 370,(1) 10 cm^ of the blood are then reintroduced into the circulation of the rabbit. 

 From the remaining blood, two standard samples, each of them weighing about 

 3 gm, are prepared. 



^^' This temperature was chosen to accelerate the penetration of labelled phos- 

 phate into the corpuscles. 



