296 



DR MATTHEWS DUNCAN ON THE 



45, have an average family of about 6 ; persistently fertile wives have an average 

 family of 104. While fertile wives married for 26 years, before and up to the age 

 of 45, have an average family of 8 ; persistently fertile wives, in the same circum- 

 stances, have an average family of about 14. While fertile wives, married for 31 

 years, before and up to the age of 45 years, have an average family of 9 ; per- 

 sistently fertile wives, in the same circumstances, have an average family which 

 may be estimated at 16. 



TABLE IV. — Showing a Comparison of the Fertility of Mothers and of 

 Persistently Fertile Mothers. 



Age at 

 Marriage. 



15-19 

 20-24 

 25-29 

 30-34 



Duration 

 of Marriage. 



At least 31 yrs. 

 At least 26 yrs. 

 At least 21 yrs. 

 At least 16 yrs. 



(St George's-in-the-East.) 



Wives Mothers. 



Number of 

 Mothers. 



Number of 

 Children. 



80 



730 



179 



1418 



100 



630 



25 



115 



Average 



fertility of 



each Mother. 



912 

 7-92 

 630 

 4-60 



(Edinburgh and Glasgow in 1855.) 



Wives Mothers bearing Children at 

 the end of Child-bearing life. 



Number of 

 Mothers. 



Number of 

 Children. 



83 

 74 



46 



Average 



fertility of 



each Mother. 



16 



13-83 

 10-57 

 11-50 



In this Table (IV.) it will be observed that the differences between the fertile 

 and the persistently fertile are much greater than in the former (II. and III.), a cir- 

 cumstance which is easily explained. For, in the latter, all the women have been 

 long married, and the persistently fertile have had time to far outrun the average 

 fertility of all the fertile. It must also be noted, that all the women in the Table 

 are fertile at or near the end of the child-bearing period, a time at which, it will 

 be hereafter shown, the intensity of fertility is greater than at any other. 



Chapter VIII. — Degrees of Fertility of Wives Mothers of Families of different 



Numbers. 



Under this head, the first question that raises itself relates to the interval 

 between marriage and the birth of the first child. In Table V. this question is 

 found fully answered. In fertile marriages generally, there intervene about 

 17 months (1-38 year) between the ceremony and the birth of the first child. 

 But in women of all ages this interval is far from being identical. As age 

 increases above 25 years, the interval increases; the hope of the female is 

 longer of being realised. The Table does not confirm this statement for wives 

 married at 40 and upwards ; but this is almost certainly a mere result of the 

 paucity of the data at these ages. The whole tenor of the Table confirms the law 

 of greatest fecundity according to age, meaning by fecundity, likelihood of having 



