GROWTH AND DIVISION OF CELLS AS 

 AFFECTED BY RADIATION 



By SIDNEY RUSS, D.Sc, 

 Physicist to the Middlesex Hospital, Fellow of University College, London 



The radiation under consideration here is that from 5 to -005 

 A.U. thus comprising X-rays, the types usually spoken of as 

 " soft," " medium," and " hard," together with the gamma 

 rays of radium. 



Such rays are now generally known to have profound 

 effects upon animal and vegetable cells. Like other agents, 

 their effects are essentially selective. A measured dose of 

 radiation of certain wave-length which is sufficient for the 

 destruction of one type of cell may be to all outward appear- 

 ances without effect upon cells of a different variety. 



The effects produced by a certain quantity of radiation, 

 however, are largely dependent upon the way in which the 

 rays are administered, i.e. the dosage employed. For example, 

 the effect of a single large dose of X-rays upon the human skin 

 is greater than that produced by repeated small doses, the 

 total quantity of radiation being the same in the two cases. 



There is at present no satisfactory explanation of the 

 action which X-rays and the rays from radium have upon 

 living cells. A good many facts have been ascertained, and 

 some quantitative observations have shown that a wide 

 range of sensitiveness to the rays exists in different types of 

 cells. Were it not for the fact that in many cases malignant 

 cells are more affected by the X-rays than are the normal 

 contiguous cells, there would obviously be little place for radio- 

 therapy in disease. When we try to push investigation further 

 in an endeavour to find out what processes in the activity of 

 the cell are particularly influenced, it must be admitted that 

 the information so far afforded is scanty. Theories have from 

 time to time appeared endeavouring to locate some specially 

 vulnerable constituent of the cell, such as for instance lecithin 

 or the chromatin of the nucleus, or again the enzymes secreted 



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