The most curious and convincing examples of superfetation are those in which children of different colors, either twins or near the same age, are born to the same woman,--similar to that exemplified in the case of the mare who was covered first by a stallion and a quarter of an hour later by an ass, and gave birth at one parturition to a horse and a mule. Parsons speaks of a case at Charleston, S.C., in 1714, of a white woman who gave birth to twins, one a mulatto and the other white. She confessed that after her husband left her a negro servant came to her and forced her to comply with his wishes by threatening her life. Smellie mentions the case of a black woman who had twins, one child black and the other almost white. She confessed having had intercourse with a white overseer immediately after her husband left her bed. Dewees reports a similar case. Newlin of Nashville speaks of a negress who bore twins, one distinctly black with the typical African features, while the other was a pretty mulatto exhibiting the distinct characters of the Caucasian race. Both the parents were perfect types of the black African negro. The mother, on being questioned, frankly acknowledged that shortly after being with her husband she had lain a night with a white man. In this case each child had its own distinct cord and placenta.

Archer gives facts illustrating and observations showing: "that a white woman, by intercourse with a white man and negro, may conceive twins, one of which shall be white and the other a mulatto; and that, vice versa, a black woman, by intercourse with a negro and a white man, may conceive twins, one of which shall be a negro and the other a mulatto." Wight narrates that he was called to see a woman, the wife of an East Indian laborer on the Isle of Trinidad, who had been delivered of a fetus 6 inches long, about four months old, and having a cord of about 18 inches in length. He removed the placenta, and in about half an hour the woman was delivered of a full-term white female child. The first child was dark, like the mother and father, and the mother denied any possibility of its being a white man's child; but this was only natural on her part, as East Indian husbands are so intensely jealous that they would even kill an unfaithful wife. Both the mother and the mysterious white baby are doing well. Bouillon speaks of a negress in Guadeloupe who bore twins, one a negro and the other a mulatto. She had sexual congress with both a negro and a white man.

Delmas, a surgeon of Rouen, tells of a woman of thirty-six who was delivered in the hospital of his city on February 26, 1806, of two children, one black and the other a mulatto. She had been pregnant eight months, and had had intercourse with a negro twice about her fourth month of pregnancy, though living with the white man who first impregnated her. Two placentae were expelled some time after the twins, and showed a membranous junction. The children died shortly after birth.

Pregnancy often takes place in a unicorn or bicorn uterus, leading to similar anomalous conditions. Galle, Hoffman, Massen, and Sanger give interesting accounts of this occurrence, and Ross relates an instance of triple pregnancy in a double uterus. Cleveland describes a discharge of an anomalous deciduous membrane during pregnancy which was probably from the unimpregnated half of a double uterus.