Israel Spach, in an extensive gynecologic work published in 1557, figures a lithopedion drawn in situ in the case of a woman with her belly laid open. He dedicated to this calcified fetus, which he regarded as a reversion, the following curious epigram, in allusion to the classical myth that after the flood the world was repopulated by the two survivors, Deucalion and Pyrrha, who walked over the earth and cast stones behind them, which, on striking the ground, became people. Roughly translated from the Latin, this epigram read as follows: "Deucalion cast stones behind him and thus fashioned our tender race from the hard marble. How comes it that nowadays, by a reversal of things, the tender body of a little babe has limbs nearer akin to stone?" Many of the older writers mention this form of fetation as a curiosity, but offer no explanation as to its cause. Mauriceau and de Graaf discuss in full extrauterine pregnancy, and Salmuth, Hannseus, and Bartholinus describe it. From the beginning of the eighteenth century this subject always demanded the attention and interest of medical observers. In more modern times, Campbell and Geoffroy-Saint-Hilaire, who named it "Grossesse Pathologique," have carefully defined and classified the forms, and to-day every text-book on obstetrics gives a scientific discussion and classification of the different forms of extrauterine pregnancy. The site of the conception is generally the wall of the uterus, the Fallopian tube, or the ovary, although there are instances of pregnancy in the vagina, as for example when there is scirrhus of the uterus; and again, cases supposed to be only extrauterine have been instances simply of double uterus, with single or concurrent pregnancy. Ross speaks of a woman of thirty-three who had been married fourteen years, had borne six children, and who on July 16, 1870, miscarried with twins of about five months' development. After a week she declared that she was still pregnant with another child, but as the physician had placed his hand in the uterine cavity after the abortion, he knew the fetus must be elsewhere or that no pregnancy existed. We can readily see how this condition might lead to a diagnosis of extrauterine pregnancy, but as the patient insisted on a thorough examination, the doctor found by the stethoscope the presence of a beating fetal heart, and by vaginal examination a double uterus. On introducing a sound into the new aperture he discovered that it opened into another cavity; but as the woman was pregnant in this, he proceeded no further. On October 31st she was delivered of a female child of full growth. She had menstruated from this bipartite uterus three times during the period between the miscarriage of the twins and the birth of the child. Both the mother and child did well.