RATE OF PENETRATION OF IONS INTO ERYTHROCYTES 499 



phosphate ions which penetrated into the corpuscles were replaced by- 

 phosphate ions located previously in the corpuscles (interchange) while 

 the other half was replaced by other anions than phosphate located 

 previously in the corpuscles (accumulation). 



In the first experiment, by adding active phosphate buffer to the 

 blood, we increased the inorganic P content of the plasma from 3.8 

 to 30.8 mgm per cent. In the second experiment, 0.1 cc. isotonic active 

 phosphate buffer was added to 3 cc. blood, increasing thus the phosphate 

 content of the plasma to 7.3 times its normal value. In the test experi- 

 ment, 3 cc. blood was shaken with 0.1 cc. isotonic NaCl solution contain- 

 ing ^^P of negligible weight. 



From 100 ^^p atoms added, the corpuscles contained 19.7 and 21.4 

 atoms, respectively, in the first experiment, and 32.0 and 32.1 atoms, 

 respectively, in the second experiment. These figures state obviously 

 the percentage of phosphate ions which migrated in the course of the 

 experiment from the plasma into the corpuscles, but they supply no 

 information about the reversed process and, thus, no information on 

 the problem how much excess phosphate was accumulated in the cor- 

 puscles. This question is discussed on p. 507. 



EFFECT OF TEMPERATURE ON THE RATE OF PENETRATION 

 OF PHOSPHATE INTO THE CORPUSCLES 



Early workers (Ege, 1919, Iversen, 1921) arrived at the result that 

 the corpuscle membrane of human and rabbit blood is only slightly 

 permeable to phosphate at 3° and that this permeability increases 

 somewhat with a rise in temperature. Halpern (1936) found later that 

 phosphate diffuses across the corpuscle membrane not at all at 3° and 

 only at a very slow rate at 23°; at 37.5°, however, the rate of diffusion 

 is greatly accelerated. Penetration of phosphate into the corpuscles was 

 tested by noting whether inorganic phosphate added to the blood would 

 enter the corpuscles or whether it would be carried out of the corpuscles 

 with water after the addition of hypertonic sodium chloride or sucrose 

 solutions to the blood. 



The application of radiophosphorus in permeability studies leads to 

 the result that the amount of phosphate penetrating the corpuscle 

 membrane is much smaller at 0° than at 37°, the permeability being, 

 however, easily determinable even at 0°. The results of such studies are 

 seen in Table 6. 



In the experiments lasting 64 and 72 minutes, in contrast to our usual 

 procedure, we washed the corpuscles once with 0.9 per cent sodium 

 chloride solution. As mentioned on p. 493, the centrifuged corpuscles 

 contain some plasma and some of the ^^P found in the corpuscle fraction 



32* 



