802 



AMERICAN MEN OF SCIENCE 



when they are babies. The figures in the 

 table mean that the fathers being on the 

 average 35 j^ears old when their sons are 

 born have an expectation of life of 35.6 

 years, and will on the average die at the 

 age of 70,6 years. The mothers, averaging 

 29.7 years old, have an expectation of life 

 of 40.5 years. These expectations are 

 about four years longer than those allowed 

 by standard mortality tables, but the data 

 are not exactly comparable. Although the 

 parents of the more distinguished scien- 

 tific men do not live longer than the 

 others, they live longer after the births 

 of their sons. 



Table XII. The Ages at Death of the Fathers 



OF the Scientific Men in accordance 



WITH THEiE Occupations 



No. 



Professions 370 



Clergymen . 94 



Physicians. . . . | 66 



Lawyers 57 



Teachers 70 



Others 83 



Agriculture 193 



Manufacture 330 



Total . 



893 



Age at Death. 



71.68 

 67.20 

 71.75 

 69.29 

 68.25 



69.67 



.81 



1.08 



1.19 



1.07 



.92 



72.81 



70.65 



.45 



.62 

 .48 



70.71 .29 



Table XII. shows that the farmers who 

 were fathers of .scientific men died at the 

 average age of 72.8 years, the physicians 

 a,t 67.2 years, a difference of over five 

 years between the shortest and longest 

 lived of the groups. The clergymen and 

 lawyers lived one year less than the farm- 

 ers, the teachers two and a half years less. 

 Those engaged in manufacturing and 

 trade died at the average age. According 

 to the report of the English registrar- 

 general (1908), the death rates per thou- 

 sand during the years 1900-1902 for those 



between 45 and 65 in different occupa- 

 tions were : Fanners, 14.8 ; clergjonen, 15.5 ; 

 teachers, 15.8 ; la\\yers, 18.3 ; physicians, 

 23.9. 



Table XIII. gives the ages at death of 

 the mothers in accordance with the size of 

 their families. The crude figures are sub- 

 ject to a statistical error, as mothers might 

 have small families because they died 

 early. This is eliminated by considering 

 only those who survived the child-bearing 

 age. In this case mothers of one child 

 died at the average of 68.6 years; mothers 

 of 12 children at the age of 80.6. There 

 are included 759 families, but the number 

 of families of different sizes, is too small to 

 give entirely valid averages. Still it is 

 significant that the thirteen mothers of 11 

 and 12 children lived to the average age of 

 78 yeaxs; the 43 mothers of 9 and 10 chil- 

 dren to the age of 75 years. It is prob- 

 able that the women who were the more 

 vigorous had the largest number of chil- 

 dren and also lived to the greatest age; 

 they might have lived as long or even 

 longer if they had been unmarried. Though 

 largely due to statistical selection, the 

 fact remains that of 45 mothers of one 

 child 10 did not survive the age of 45, 

 whereas of 56 mothers of from 9 to 12 

 children not one died under this age. In 

 view of these faets it may be doubted 

 whether the practise of limiting the num- 

 ber of children is beneficial to the health 

 and longevity of the mother. 



Table XIV. gives the numbers of scien- 

 tific men who were first-born children, 

 second-born children, etc., for each size of 

 family. A scientific man is of course more 

 likely to be a first-born child than a sec- 

 ond-born, because there are families with 



