280 Reproductive Selection 
From these figures may be derived the numbers of survivors to age 80 of every 
1000 who attain age 5 and which are as follows : 
Sweden 178 
Norway 192 
Belgium 134 
Switzerland 92 
New South Wales 137 
From this it is seen that those countries with one exception — France — with 
heavy mortality under 5 years of age do not yield as favourable a result at age 80 
even after such a severe weeding out, as those countries where the mortality under 
5 is light. 
E. Reproductive Selection. 
Professor Pearson says* with regard to the question "Does Society ultimately 
recruit itself from above or below ? " 
" (a) The fertility of one class must be shown to be sensibly greater than that 
of another class. Now the causes of fertility for two classes in the same com- 
munity differ comparatively slightly. Hence the small but sensible effect of 
natural selection must be carefully estimated and allowed for, i.e., we must deal 
with net fertilities. 
"(6) But the net fertility of one class may still be greater than that of a 
second and yet the second increase at a greater rate. We have to determine 
how far the greater fertility is merely potential. We must ascertain what propor- 
tion of the two classes remain unmated. 
" (c) Not only may the net fertility be greater — i.e., the number of children 
per family who survive infancy, say live to 15 years, be greater — but also the per- 
centage of mating may be greater in one class than another and yet the same class 
may yet have no reproductive advantage. We ought further to take into account 
the adult death rates in the two classes. Natural selection may not only be 
effective in modifying the gross fertility into a net fertilitj' but also as an adult 
death rate." 
The "Vital Statistics" of New South Wales for the years 1895 to 1899 
inclusive throw much light upon this question of reproductive selection. In them 
tables will be found showing the occupations of married men who died during that 
period together with the total offspring — distinguishing the living and dead. The 
ages of the living offspring are not given, so that the net fertility must be regarded 
as the number of offspring living at the time of the death of the father and 
irrespective of their ages. Thus the conditions contained in (o) and (c) above 
except that the net fertility is as just stated are fairly complied with, and as the 
* The Chances of Death, Vol i. pp. 96 and 97. 
England 126 
France 138 
Prussia 95 
Austria 72 
Italy 103 
Spain 121 
