238 P. L. Mollison 



are different processes. It has already been mentioned that 

 changes in the sodium and potassium content of red cells 

 during storage are reversible after transfusion. It has been 

 shown that changes in the content of organic phosphate com- 

 pounds are reversed within three hours of transfusion but are 

 not reversed by incubation for 24 hours in vitro with fresh 

 plasma (Gabrio et al., 1954). 



It is possible that ATP plays an important role in the main- 

 tenance of viability of normal red cells. It has, for example, 

 been shown that in hereditary spherocytosis, in which the life- 

 span of red cells is greatly reduced, the rate of ATP formation 

 is diminished (Prankerd, Altaian and Young, 1954). It is also 

 known that reticulocytes contain two or three times as much 

 ATP as mature red cells (Granick, 1949). However, work in 

 this field is still in an early stage. 



All that we can say at the present time is that ageing of red 

 cells almost certainly consists in the gradual using up of an 

 initial supply of "fuel" that cannot be replaced, and that 

 changes occurring in red cells during storage probably tell us 

 very little about ageing in vivo. 



REFERENCES 



Allison, A. C, and Burn, G. P. (1955). Brit. J. Haematol., 1, 291. 



Altman, K. I. (1953). Arch. Biochem. Biophys., 42, 478. 



Brown, I. W. Jr., and Eadie, G. S. (1953). J. gen. Physiol., 36, 327. 



Chaplin, H. Jr., Crawford, H., Cutbush, M., and Mollison, P. L. 

 (1956). Clin. Sci. (In press.) 



Crawford, H., Cutbush, M., and Mollison, P. L. (1955). To be pub- 

 lished. 



Crawford, H. and Mollison, P. L. (1955). J. Physiol., 129, 639. 



Cruz, W. O., Hahn, P. F., Bale, W. F., and Balfour, W. M. (1941). 

 Amer. J. med. Sci., 202, 157. 



Dornhorst, A. C. (1950). In conversation. 



Gabrio, B. W., Donohue, D. M., and Finch, C. A. (1955). J. clin. 

 Invest, 34, 1509. 



Gabrio, B. W., Stevens, A. R. Jr., and Finch, C. A. (1954). J. clin. 

 Invest, 33, 252. 



Granick, S. (1949). Blood, 4, 404. 



Hughes Jones, N. C, and Mollison, P. L. (1956). Clin. Sci. (In press.) 



Hurley, T. H., and Weisman, R. Jr. (1954). J. clin. Invest., 33, 835. 



Loutit, J. F., Mollison, P. L., and Young, I. M. (1943). Quart. J. exp. 

 Physiol, 32, 183. 



