AND FECUNDITY OF WOMEN ACCORDING TO AGE. 



487 



TABLE XII. — Shoaving the Initial Fecundity of Women under 20 Years of Age 

 WITHIN THE First Two Years of Marriage. 



Ages of Wives newly Married, 



16 



17 



18 



19 



No. of Wives newly Married, 



No. of Wives Mothers within two years of Marriage, 



Proportion of latter to former is 1 in 



Proportion after correction for Immaturity is 1 in . 



43 



4 



10-7 



7-7 



108 

 27 

 4-0 

 3-3 



225 

 98 

 2-3 

 2-1 



314 

 177 

 1-8 

 1-7 



Percentage, 



12-90 



30-00 



46-44 



57-84 



The commencement of menstruation is generally considered by physicians an 

 indication of the arrival of sexual maturity. It may be true that some are still 

 immature in whom this phenomenon has shown itself, and it certainly is true 

 that some are mature before its appearance. Yet it forms a generally accredited 

 indication of maturity. The following table (XIII.), framed by Dr Whitehead, 

 is a large collection of data, showing the age of the appearance of menstrua- 

 tion in 4000 individuals in this country. It is easy to calculate what fraction of 

 the whole 4000 had begun to menstruate at 16, 17, 18, and 19 years of age re- 

 spectively, or, in other words, what fraction was capable of exhibiting fecundity 

 at these ages. This I have done, and have corrected the numbers of wives in 

 tables eleventh and twelfth accordingly, reducing them to similar fractional parts. 

 After making this correction for immaturity, I have calculated the proportions 

 of wives-mothers to wives, and placed the results in the last line- They remain 

 the same so far as to show a steady diminution of fecundity as age diminishes. 



TABLE XIII. — " Showing the Age at which Puberty was accomplished in Four 

 Thousand Individuals." (Whitehead, on Sterility and Abortion, p. 46.) 



At Age of 19 years 148 first Menstruated. 



At Age 



of 10 



years 



9 first Menstruated 



)) 



11 





26 







> 



12 





136 







t 



13 





332 







) 



14 





638 







) 



15 





761 







) 



16 





967 







)j 



17 





499 









18 





393 





20 





71 



21 





9 



22 





6 



23 





2 



24 





1 



25 





1 



26 





1 



From these data I conclude— 



1. That the initial fecundity of women gradually waxes to a climax, and then 

 gradually wanes. 



vol. XXIII. PAKT III. 6 Q 



