INTERACTION OF PLASMA PHOSPHATE WITH THE PHOSPHORUS COMPOUNDS 483 



was injected into the ear vein of a rabbit drop by drop in the course 

 of the experiment which look 3 hours. During the experiment small 

 blood samples (0.1 — 0.3 mgm) were taken from the vein of the other ear 

 of the rabbit and their activity determined. The results of the experiment 

 are seen in Tables 5 and 6. 



T.\BLE 6. — Specific Activities Obt.a.inei) 

 Labelled P injected drop b>- drop during the coui-se of the experiment (3 hours) 



Fraction 



Relative specific 

 activity 



Plasma inorganic P 



Corpuscle inorganic P 



Corpuscle acid-soluble organic P 



Marrow inorganic P 



Muscle inorganic P 



Muscle creatine P 



Muscle acid-soluble after removal of inorganic creatine P 

 TiVjia diaphysis P average 



100.0 

 ll.O 

 7.7 

 7.") 

 6.i» 

 0.95 

 0.78 

 0.27 



As seen from the figures of Table 5 the specific activity of the plasma 

 inorganic P ' increases during the experiment somewhat slow^er than 

 proportional to time. If the increase of the specific activity would be 

 proportional to the time of the experiment the average specific activity 

 of the plasma inorganic P, which we wish to know, should be = ^S^. 

 This can be considered to be a lower limit of the average specific activity. 

 To arrive at an upper limit we could assume the average specific activity 

 to be equal to the maximum value observed, which is Sp. Making the 

 assumption Sp = prop, yi, we arrive at the average value of the specific 

 activity of the plasma inorganic P = i Sp. The value for the specific 

 activity of the total acid-soluble corpuscle P (comp. p. 477) is approxima- 

 tely given by the formula 



S^ = 2^ t (Sp- 1.8 S,) . 



g 



For the ratio— ^, after the lapse of 175 min., we arrive at the figure 



Sp 



0.12 (using the value of a found in our experiments in vitro), while the 

 experimental value of the specific activity of the acid-soluble P of the 

 corpuscles (comp. Table 6), after the lapse of 175 min., was found to be 



Sc 



8% of the plasma inorganic P at the same time, or— =0.08. The 



Sp 



calculated and experimentally found values of the rate of labelling of 

 31* 



