444 THE SCIENTIFIC MONTHLY 



THE BIOLOGY OF DEATH. HI— THE CHANCES 

 OF DEATH 1 



By Professor RAYMOND PEARL 



the johns hopkins university 



1. The Life Table 



"P to this point in our discussion of death and longevity we have, 

 for the most part, dealt with general and qualitative matters, 

 and have not made any particular examination as to the quantitative 

 aspects of the problem of longevity. To this phase attention may now 

 be directed. For one organism, and one organism only, do we know 

 much about the quantitative aspects of longevity. I refer, of course, 

 to man, and the abundant records which exist as to the duration of his 

 life under various conditions and circumstances. In 1532 there began 

 in London the first definitely known compilation of weekly "Bills of 

 Mortality." Seven years later the official registration of baptisms, 

 marriages and deaths was begun in France, and shortly after the open- 

 ing of the seventeenth century similar registration was begun in 

 Sweden. In 1662 was published the first edition of a remarkable book, 

 a book which marks the beginning of the subject which we now know 

 as "vital statistics." I refer to "Natural and Political Observations 

 Mentioned in the Following Index, and made upon the Bills of Mor- 

 tality" by Captain John Graunt, Citizen of London. From that day to 

 this, in an ever widening portion of the inhabited globe we have had 

 more or less continuous published records about the duration of life in 

 man. The amount of such material which has accumulated is enor- 

 mous. We are only at the beginning, however, of its proper mathe- 

 matical and biological analysis. If biologists had been furnished with 

 data of anything like the same quantity and quality for any other 

 organism than man one feels sure that a vastly greater amount of atten- 

 tion would have been devoted to it than ever has been given to vital 

 statistics, so-called, and there would have been as a result many funda- 

 mental advances in biological knowledge now lacking, because material 

 of this sort so generally seems to the professional biologist to be some- 

 thing about which he is in no way concerned. 



Let us examine some of the general facts about the normal duration 

 of life in man. We may put the matter in this way: Suppose we 

 started out at a given instant of time with a hundred thousand infants, 



Papers from the Department of Biometry and Vital Statistics, School 

 of Hygiene and Public Health, Johns Hopkins University, No. 30. 



