DETERMINATION OF IJED CORPUSCLE CONTENT 



525 



the average of the activity of 1 gm of corpuscles secured from 12 rabbits 

 after 3, 5, 7, 9, and 15 min, respectively, is stated. The values obtained 

 after 5, 7, and 9 min do not differ from each other within the error of 

 experiments (zb 5 per cent). The value obtained after the lapse of 15 

 min, possibly indicates a slight loss of ^sp by the labelled corpuscles. 

 The fact that, within a time amply sufficient to carry out determination 

 of the corpuscle volun e, the label of the corpuscles remains conserved is due 

 partly to the comparatively slow rate of passage of the phosphate ions 

 1 hrough the corp\iscle wall, and partly to the fact that the easily renewable 

 (activated) acid soluble P content of the corpuscles is much higher than 

 the corresponding fraction of the plasma. The major part of the ^^p 



Table 1. — Activity of 1 gj* Corpuscles Secured from Different Rabbits ai 

 Different Times after the Injection of Labelled Blood (Corpuscles) 



which entered the corpuscles while the blood was shaken in the thermo- 

 stat is present as easily exchangeable organic acid soluble P. Now, the 

 ^2P atoms have the same chance to leave the corpuscles as have the ^^P 

 atoms present in the same state. The ratio of ^ap and ^ip atoms in the 

 corpuscles is, however, much smaller than the corresponding ratio in 

 the plasma. Correspondingly, the chance of a ^^p atom to leave the 

 corpuscles is comparatively small. The corpuscles of 100 gm of rabbit 

 blood contain about 20 mgm easily renewable acid soluble P atoms, while 

 the plasma contains only about 2 mgm P atoms; the ^ap content of 1 gm 

 corpuscles in the labelled blood injected is about the same as the ^sp 

 content of 1 gm plasma. The ^^p atoms have thus a much greater chance 

 to enter the corpuscles than to migrate in the opposite direction. Of 

 course, if an exchange equilibrium of ^^p between plasma and corpuscles 

 is reached, this statement is no longer valid, but — as follows from the 



