CHAPTER IV 

 THE CAUSES OF DEATH 



IT has been suggested in earlier chapters that natural 

 death of the metazoan body may come about fundamen- 

 tally because of the differentiation and consequent mu- 

 tual dependence of structure and function of that 

 body. It is a complex aggregate of cells and tissues, 

 all mutually dependent upon each other and in a 

 delicate state of adjustment and balance. If one organ 

 for any accidental reason, whether internal or external, 

 fails to function normally it upsets this delicate balance, 

 and if normal functioning of the part is not promptly 

 restored, death of the whole organism eventually results. 

 Furthermore, it is apparent that death does not strike in 

 a haphazard or random manner, but instead in a most 

 orderly way. There are certain periods of life notably 

 youth where only an insignificant fraction of those ex- 

 posed to risk ever die. At other ages, as, for example, 

 extreme old age and early infancy, death strikes with 

 appalling precision and frequency. Further we recall 

 with Seneca that nascimus uno modo multis morimur. 

 Truly there are many ways of dying. The fact is obvious 

 enough. But what is the biological meaning of this mul- 

 tiplicity of pathways to the river Styx? There is but 

 one pathway into the world. Why so many to go out? 

 To the consideration of some phases of this problem 

 attention is directed in this chapter. 



By international agreement among statisticians the 

 causes of human mortality are, for statistical purposes, 



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