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. CHAPTER II. PRENATAL ANOMALIES. Extrauterine Pregnancy.--In the consideration of prenatal anomalies, the first to be discussed will be those of extrauterine pregnancy. This abnormalism has been known almost as long as there has been any real knowledge of obstetrics. In the writings of Albucasis, during the eleventh century, extrauterine pregnancy is discussed, and later the works of N. Polinus and Cordseus, about the sixteenth century, speak of it; in the case of Cordseus the fetus was converted into a lithopedion and carried in the abdomen twenty-eight years. Horstius in the sixteenth century relates the history of a woman who conceived for the third time in March, 1547, and in 1563 the remains of the fetus were still in the abdomen.