59. That the embryo probably lives in utero in virtue of its own life-principle, even through the entire period of gestation, (51, 56, and 58,) is rendered probable by many facts related by unimpeached authorities, which go to prove that when the whole intact Ovum has been expelled at an advanced period of gestation, or at the natural termination of that period, the fœtus has continued to live, and the circulation of the blood has not ceased for an instant during a space of time of from nine minutes to a quarter of an hour. (Roederer, Wrisberg, Osiander, and Meckel, who repeated the experiments of the latter.) It has been asserted by a venerated authority that in an intact Ovum, expelled at seven months, the fœtus lived upwards of an hour. (Harvey.) The truth of this assertion is confirmed by very recent observers (Green, Velpeau, Gardien, Dr. Campbell)[9]. I once destroyed a female cat by prussic acid near the time of parturition; and having removed from the horns of the uterus the entire Ova, with their beautiful annular placentæ, while the fœtus in each of them was still perfectly lively, and could distinctly be seen, through the membranes, to move, I found that at the end of thirty-five, forty, and even forty-two minutes, some of them were still alive, the Ova remaining entire all the time, and upon the table[10]. 60. When the Ovulum has made good its fastening to the adventitious lining of the womb (decidua), the circulation of the blood in it is as yet imperfect. The Ovulum does not—cannot—receive the blood of the mother. How could such a gossamer-like being, organized as the Ovulum has been proved to be, during the first days after fecundation, be made a part of so impetuous a torrent as the circulation of the blood of the mother, without instant destruction to the produce of conception? No. The blood of the embryo is first formed within itself. (Prevost, Home, Magendie, Adelon, Serres, Rolando.) 61. The newly-engendered being passes through two striking metamorphoses previously to the enjoyment of its extra-uterine life. These are the Embryonic and the Fœtal states. The latter succeeds immediately to the former; beginning at the moment when the new being is grafted on the maternal womb, and continuing until its expulsion from thence at the full period of gestation. It follows, therefore, that the Embryonic or former state is that in which the new being is as yet, without any direct or indirect communication with the mother, and still less so with external objects. This state persists for about two weeks after fecundation, during which the Embryo continues to derive its nourishment from the cortical membrane of the Ovum. (Boer, Soemmering, Plagge, myself.)