THE CHANCES OF DEATH 101 



Now we have experimental proof, to be discussed in a 

 later chapter, that with complete homogeneity of the 

 material, both genetic and environmental, one gets just 

 the same kind of d^ line as in normal human material. 

 We must then, I think, come to the conclusion that bril- 

 liant and picturesque as is Pearson's conception of the 

 five Deaths, actually there is no slightest reason to sup- 

 pose that it represents any biological reality, save in the 

 one respect that his curve fitting demonstrates, as any 

 other equally successful would, that deaths do not occur 

 chaotically in respect of age, but instead in a, regular 

 manner capable of representation by a mathematical 

 function of age. 



An interesting and suggestive analysis of the dx line, 

 resting upon a sounder biological basis than Pearson's, 

 has lately been given by Ame Fisher. He breaks the 

 curve up into 8 or 9 components, based upon the compar- 

 atively stable values of the death ratios for different 

 groups of diseases characteristic of different ages. The 

 resulting total curve fits the facts from age 10 on, very 

 well, and makes possible the calculation of a complete 

 life table from a knowledge of deaths only. 



