LAWS OF THE FERTILITY OF WOMEN. 293 



Chapter V. — The Fertility of Persistently Fertile Marriages lasting during 

 the whole Child-bearing Period of Life. 



This subject may also be conveniently stated in the form of a question. How 

 many children does a fertile woman produce, living in wedlock from 15 to 45 

 years of age, and bearing children periodically up to the end of that time ? 



To this question I cannot give at once an answer founded on sufficient data ; 

 and I shall invert my usual mode of proceeding, stating the conclusion, namely, 

 that 15 at least is the average number of children borne by a persistently fertile 

 female in 30 years, before giving the reasons for it. These are as follows: — 

 A persistently fertile woman, at all ages, is found to have borne one child about 

 every 2 years ; the average fertility of 15 mothers who have had each 26 years of 

 persistently fertile life is 13. The fourth Table, to be hereafter given, showing an 

 excess of fertility on the part of those long persistently fertile, or bearing children 

 in the year of counting, would give 16 as the proportional fertility of 30 years of 

 persistently fertile marriage, calculating from the actual values given for the 

 other results in the Table. The deficiency of actual facts for settling this point is 

 to be seen in the next Table (II.), where the number of women bearing children 

 when above 26 years married, is only 7. 



On this subject Allen Thomson makes the following statement, which is 

 remarkably accurate, seeing that it is apparently not founded on any analysis of 

 documents. "A healthy woman," says he,* "bearing during the whole time, 

 and with the common duration of interval, may have in all from 12 to 16 

 children, but some have as many as 18 or 20." 



Chapter VI. — Fertility of Persistently Fertile Wives at different Years of 



Mar?*ied Life. 



The following Table (II.), from the 1855 Edinburgh and Glasgow data, gives 

 at a glance the rate of yearly increasing production of wives mothers who are 

 still fertile — that is, who produced a living child in the year of our census or 

 counting. It is framed by adding together the whole children born of mothers 

 having different durations of marriage, and dividing the sum by the number of 

 mothers corresponding to each duration of marriage. The results will be found, 

 on the whole, to tally pretty closely with those given in Table VI. It is easy to 

 account for the differences between the two Tables. In the latter Table the wives 

 arrived at different numbers of progeny are collated and compared, while in the 

 former the wives arrived at different durations of marriage are collated and 

 compared. The Table requires no further explanation ; it is easily read. 



* Todd's Cyclopsedia of Anatomy and Physiology, vol. ii. p. 478. 



