522 BLOOD VOLUME DETERMINATION 



we can, therefore, claim that, when applying the method described in 

 this note, no non-physiological component is introduced into the cir- 

 culation. As to the i^ -radiation emitted by the ^^P atoms present in the 

 corpuscle phosphatides, the number of /? -particles emitted per minute 

 in the total circulation of rabbit A amounts to only about 1000, while 

 the number emitted by the total acid-soluble fraction amounts to about 

 30 times that figure. How insignificant these figures are, can best be 

 realized when we envisage that this radiation corresponds to that of 

 only 10^^ and 10"^ gm radium, respectively. 



When carrying out experiments as those decribed above on human 

 subjects, it may be advisable to make use of the acid-soluble P com- 

 pounds of the corpuscles as indicators. Since, in this case, one may use 

 less radioactive P, such experiments can be carried out on human sub- 

 jects by administering by subcutaneous injection or by mouth to the 

 blood donor sodium phosphate having a /5-radioactivity corresponding 

 to that of about 0.01 milliCurie or even less. 



Summary 



A method of blood volume determination based on the determination of the 

 dilution of labelled corpuscles is described. Radioactive sodium phosphate is 

 administered to rabbit B; after the lapse of some days, a known blood sample 

 of this rabbit is injected into the vein of rabbit A. A few minutes later, the cor- 

 puscles of a Ivnown volume of the blood of rabbit A are secured, their phospha- 

 tide content extracted, and its activity measured. Corpuscles of a known blood 

 volume of rabbit B are treated in the same way. From the ratio of the labelled 

 phosphatide P content of the corpuscles of rabbit A and rabbit B, the total blood 

 volume of rabbit A is calculated. 



An alternative and often preferable determination is based on the comparison 

 of the activity of the acid-soluble P secured from the corpuscle samples of rabbi t 

 A and rabbit B. 



The blood volume per kgm of rabbit weight is found to be 42 cc, per kgm of 

 chick weight 45 cc. 



Literature 



E. V. Behring (1912) Beitr. Z. exp. Ther. 12, 2. 



C. C Fleischer— Hansen (1928) Studier over Blodvolumen. Copenhagen. 



S. Graff, O. A. d'Esopo and A. J. B. Tillmann (1931) Arch. Int. Med. 48, 821. 



L. Hahn and G. Hevesy (1940) Kgl. Danske Vidensk. Selsk. Biol. Medd. (in 



print). 

 E. Madsen (1934) Acta path, microbiol. Scand. 11, 376. 

 L. G. RowNTREE, G. E. Brown and G. M. Roth (1929) The Volume of the Blood 



and Plasma in Health and Disease. Philadelphia. 



