NOTE.—­In an article entitled “Sur le nombre des consanguins dans un groupe de population,” in Archives italiennes de biologie (vol. xxxiii, 1900, pp. 230-241), Dr. E. Raseri shows that from one point of view the actual number of consanguineous marriages is little, if any, greater than the probable number.  The average number of children to a marriage he finds to be 5, the average age of the parents 33 and the average age at marriage 25.  The Italian mortality statistics show that 54 per cent of the population lives to the age of 25, of which 15 per cent does not marry, leaving an average of 2.3 children in every family who marry.  On this basis a person would have at birth 4,357 relatives within the degree of fourth cousins; at the age of 33 he would have 4,547; and at 66, 5,002.  In 1897 out of 229,041 marriages in Italy, 1,046 were between first cousins, giving an average of one in 219.  In 1881 the number of men between 18 and 50 and of women between 15 and 45 was 5,941, 495 in 8,259 communes with an average 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.

Within recent years the theory has prevailed among certain sociologists that positive masculinity is stronger in the offspring of consanguineous marriages than in the offspring of unrelated parents.  Professor William I. Thomas in his writings and lectures asserts this as highly probable.[28] Westermarck,[29] to whom Professor Thomas refers, quotes authorities to show that certain self-fertilized plants tend to produce male flowers, and that the mating of horses of the same coat color tends to produce an excess of males.[30]