AND FECUNDITY OF WOMEN ACCORDING TO AGE. 479 



1. That the actual, not the relative, fertility of our female population, as a 

 whole, at different ages, increases from the commencement of the child-bearing 

 period of life, until the age of 30 is reached, and then declines to its extinction 

 with the child-bearing faculty. 



2. That the actual fertility is much greater before the climax, thirty years, is 

 reached, than after it is passed. 



3. That at least three-fifths of the population are recruited from women not 

 exceeding 30 years of age. 



Before leaving these tables, it is expedient to direct attention to a striking 

 lowness of figure at the ages of 29 and 31 respectively in Dr Collins's data. A 

 similar fall on each side of the highest number occurs in Dr Granville's table, 

 which has been referred to, and in every similar table which I know. This 

 curiosity has given rise to very natural and ingenious speculation. Dr Granville 

 suggests, that by the earlier decrement, nature means to rest awhile and gather 

 strength for the enormous jump she is to make in the following year, and that by 

 the second decrement she means to evince the exhaustion which invariably follows 

 over- exertion. But I cannot acquiesce in this fanciful hypothesis, believing that 

 really no such decrement, jump, and second decrement, occur. My explanation of 

 this tabular phenomenon is suggested by the occurrence of similar falls on each 

 side of the age of 40 years, in Collins's table, and in my own and in others. I am 

 too well aware, from ample experience, of the impossibility of getting women's 

 ages stated correctly, especially if they have passed twenty-five years, and 

 have often observed, that when pushed, they say 30 or 40 as a round easy 

 number ; and the state of the tables appears to me merely to indicate that women 

 of about 31 and of 41 years of age frequently say they are 30 and 40 years old 

 respectively. In short, these decrements are evidence of the unfortunate element 

 of error Avhich creeps into the most carefully prepared vital statistics on a large 

 scale. 



Chapter II. — The Comparatim Fertility of the Female Population as a whole at 



Different Ages. 



Having shewn the actual fertility of women at different ages in our popu- 

 lation, I now proceed to the question of the comparative productiveness of our 

 whole female population at different ages. To settle this, it is only necessary to 

 compare the number of children born of women of different ages with the number 

 of women living at the different ages respectively. The result of the calculations 

 involved in this comparison will be to show, not simply (as in Chapter I.,) the 

 numbers of children born of women at different ages, but the number of mothers 

 relatively to the number of women living at different ages — in other words, the 

 comparative fertility or productiveness of our female population as a whole at 

 different ages. 



vol. XXIII. part III. 6 o 



