defect was common, in the course of a few generations that defect would be found in a relatively large part of the population.  While if the same island were settled by perfectly sound families, there would only be a remote chance of any particular defect appearing.  Thus both classes of investigators may be perfectly conscientious, and yet arrive at diametrically opposite results.  This theory is at least not to be contradicted by any facts which have come to light in the present investigation.

Some interesting points are brought up in Dugdale’s well-known study of the “Jukes."[53] This family, of about 540 persons living in northern New York, is descended from five sisters of unknown parentage, who were born between 1740 and 1770.  The name “Juke” is fictitious, and is applied to all descendants of these five women, little attempt being made to trace the male lines on account of the excessive prevalence of illegitimacy.

[Footnote 53:  R.L.  Dugdale, The Jukes]

In this family consanguineous marriages have been very frequent, perhaps partly because the Jukes came to be looked upon as pariahs and could not associate on equal terms with other members of the community.  These marriages seem to have been fully as productive as the average of the family, and the offspring of as high a grade of intelligence.  However, some individual cases are worthy of special mention as illustrative of intensification of hereditary tendencies.

(1) An illegitimate son of Ada Juke married a daughter of Bell Juke.  He was a laborer, honest and industrious.  She was reputable and healthy, and her father had a good reputation, but her mother had given birth to four illegitimate children before marriage, three of whom were mulattoes.  Thus in this marriage of first cousins, three out of the four parents were of a low moral grade.  As a result of this marriage three sons and three daughters were born.  Two sons were licentious, intemperate and dishonest, two daughters were prostitutes, and the third became such after her husband was sent to prison.  Only one son turned out fairly well.  This son married a second cousin, a granddaughter of Delia Juke, and four out of his seven children were above the average of the family.  His two elder brothers, however, married prostitutes, and became ancestors of criminals, prostitutes and syphilitics.[54]

[Footnote 54:  Ibid., Chart I.]

(2) A legitimate son of Ada Juke, whose father was a thief and a pauper, married a daughter of Clara Juke, whose antecedents were fairly good.  The husband had contracted syphilis before marriage and entail it upon every one of his eight children.  Five daughters became prostitutes and one was idiotic.  The only daughter who bore a good reputation married a grandson of both Clara and Bell Juke.  This was a remarkable case of selection.  Both husband and wife were grandchildren of Clara, and so first cousins, and both were the offspring of first cousins,