population of 3,500. In each commune there must be 360 marriageable
persons of each sex, but to marry within his class a man would only
have the choice of 180 women and vice versa. Adding the probable
number who would marry outside the commune, the choice lies within 216
of the opposite sex. Of these 25 would be cousins within the tenth
degree (fourth cousins) making the probability of a consanguineous
marriage .11, reduced by a probable error in excess to .10. The
probability of a first cousin marriage would be .82/216 or .0038,
whereas the actual ratio is 1/219 or .0045.




CHAPTER III

MASCULINITY


The predominance of male over female births is almost universal,
although varying greatly in different countries and under different
conditions. This fact has given rise to the term Masculinity, which
conveniently expresses the proportion of the sexes at birth. The
degree of masculinity is usually indicated by the average number of
male births to every 100 female births. The cause of this
preponderance of males is still a mystery, and will definitely be
known only when the causes of the determination of sex are known.
Since, however, it is well known that infant mortality is greater
among males than among females, positive masculinity is necessary to
keep up the balance of the sexes, and therefore seems to be an
essential characteristic of a vigorous and progressive race.