THE BIOLOGY OF DEATH 455 



mortality. It accounts for 46.4 deaths out of the total of 1,000. Its 

 range and variability are obviously less than those of any of the other 

 three components so far considered. The last, excessively skew com- 

 ponent, is that which describes the mortality of infancy. It is given 

 by a J shaped curve accounting for 245.7 deaths after birth, and an 

 antenatal mortaliy of 605. In order to get any fit at all for this por- 

 tion of the mortality curve it is necessary to assume that the deaths 

 in utero and those of the first months after birth are a homogeneous 

 connected group. 



Summing all these components together it is seen that the resulting 

 smooth curve very closely fits the series of small circles which are the 

 original observations. From the standpoint merely of curve fitting 

 no better result than this could be hoped for. But about its biological 

 significance the case is not quite so clear, as we shall presently see. 



Pearson himself thinks of these five components of the mortality 

 curve as typifying five Deaths, shooting with different weapons, at 

 different speeds and with differing precision at the procession of human 

 beings crossing the Bridge of Life. The first Death is, according to 

 Pearson, a marksman of deadly aim, concentrated fire, and unremitting 

 destructiveness. He kills before birth as well as after and may be 

 conceived as beating down young lives with the bones of their an- 

 cestors. The second marksman who aims at childhood has an extremely 

 concentrated fire, which may be typified by the machine gun. Only be- 

 cause of the concentration of this fire are we able to pass through it 

 without appalling loss. The third marksman Death, who shoots at 

 youth has not a very deadly or accurate weapon, perhaps a bow and 

 arrow. The fire of the fourth marksman is slow, scattered and not very 

 destructive, such as might result from an old fashioned blunderbus. 

 The last Death plies a rifle. None escapes his shots. He aims at old 

 age but sometimes hits youth. His unremitting activity makes his 

 toll large. 



We may let Pearson sum the whole matter up in his own words: 

 "Our investigations on the mortality statistics have thus led us to some 

 very definite conclusions with regard to the chances of death. Instead 

 of seven we have five ages of man, corresponding to the periods of in- 

 fancy, of childhood, of youth, of maturity or middle age, and of 

 senility or old age. In the case of each of these periods we see a per- 

 fectly regular chance distribution, centering at a given age, and tailing 

 off on either side according to a perfectly clear mathematical law. . . 



"Artistically, we no longer think of Death as striking chaotically; 

 we regard his aim as perfectly regular in the mass, if unpredictable in 

 the individual instance. It is no longer the Dance of Death which pic- 

 tures for us Death carrying off indiscriminately the old and young, the 

 rich and the poor, the toiler and the idler, the babe and its grandsire. 

 We see something quite different, the cohort of a thousand tiny mites 



