12 Mr. T. R. Edmonds on the Law of Human Mortality 



this formula. The coincidence, at this period of life, which 

 establishes the truth of the new formula, establishes at the same 

 time the great credit for accuracy due to the English observa- 

 tions at periods of life in which the returns are not affected by 

 the disposition of the people to understate or overstate their 

 ages. 



Comparing the observations of Sweden in the present century 

 with the observations of Sweden and Finland in the previous 

 century, there is found in the more recent observations a consi- 

 derable decrease in the mortality at all ages under 20 years, and 

 a considerable increase in the mortality at all ages above 30 

 years. Both sets of observations are in accordance with the 

 new formula, but the place of the ideal zero of life in the period 

 of manhood appears to have receded in the present century three 

 or four years. 



The place of the ideal zero of life for the period of childhood 

 has been seen to be at 2^ years, or 27 months before the time of 

 birth. That is to say, when units of 9 months are taken, the 

 place of such zero is distant three of such units from the time 

 of birth, -or two of such units from the time of conception. 



It has been found, through observations collected by Dr, Gran- 

 ville at lying-in hospitals, that out of about 450 pregnant women 

 150 had suffered miscarriage, the average proportion being one 

 miscarriage to two births alive, and that the number of miscar- 

 riages was much greater in the earlier months of pregnancy than 

 in the later months, the remaining 300 pregnant women having 

 suffered no miscarriages. The statements thus made accord 

 well enough with the assumption that the miscarriages during 

 the first seven months of pregnancy are represented by the deaths 

 which would occur if the law of mortality after birth- time were 

 continued backwards to the time of conception. On this assump- 

 tion the mortality at the commencement of uterine life, or im- 

 mediately after the time of conception, would be 56 - 9 per cent, 

 per annum, the corresponding mortality at birth-time being 

 22*4, and at age 9 years being 0'55 per cent, per annum. This 

 result, leading to the conclusion that 56*9 per cent, is the maxi- 

 mum rate of mortality capable of being measured or regulated 

 by the new formula, is indirectly confirmed by the last English 

 life Table for males, wherein it is stated that 55 per cent, per 

 annum is the highest rate of mortality observed at the most 

 advanced age. 



According to the new formula, extending over two periods, 

 bounded as stated by the ideal zeros of life at — 2| and +102 

 years of age (with a mortality of 0*55 per cent, from the age of 

 9 to the age of 12 years, common to both periods), the rate of 

 mortality at birth-time is equal to the mortality at the age 84 



