Are also examples of denuded or diaphanous Ova, to which the same remarks apply as to the preceding specimen. The enlargement of Ovum 8 is even greater than that of Ovum 9: yet the embryo of the latter is more advanced and more clearly delineated by nature than is the case with Embryo 8. We know that these two Ova and No. 7, are more than two months old from the length of the umbilical cord as compared to that of the fœtus: for from the second to the sixth month of pregnancy, the length of the cord is proportionately greater than that of the fœtus.—(See Meckel and others.)
In examining these denuded or diaphanous Ova, I have been struck with that small circular spot on their surface, generally of an opaque colour, which has been called the cicatricula, and is not unlike that which is found in some of the Ova of birds. This spot is well marked by the artist in the last three specimens, and in two of the figures of Plate 3. I take the cicatricula to be that part of the Ovulum which adhered to its ovarian nest (called the vesicula graafiana), before it burst from the Ovarium to pass into the womb consequently on fecondation. It is to be seen on all the ovula so situated in the Ovaria of women, and is considered to contain the rudiments of the embryo, which certainly begin from a little straight line that may be distinctly seen in the cicatricula.—(See Meckel, Adelon, Geoffroy St. Hilaire, Prevost, &c.)
REMARKS.
This class of human Ova throw no inconsiderable light on the progress of fœtal intro-uterine life. They prove that the embryo, called into existence by the mysterious act of fecondation (the only point that is mysterious about the process of generation according to Cuvier) may, and will, and does live independently of the mother,—with a life wholly its own, and that it derives from its parent growth only, or accretion of substance, as I stated in my preliminary observations. The museum of the Royal College of Surgeons supplies a most striking illustration, and I may add, corroboration of this opinion.
No. 3448 is a single spherical denudated diaphanous Ovum about six inches in diameter, without the slightest appearance of any placenta, filiform or cotyledonous vessels, or other of the nutritive involucra or membranes. The secreting or amnionic membrane, is capable of containing more than six ounces of fluid; yet the embryo is not larger than an embryo at one month. When this specimen was sent by Mr. Lugar, of Richmond, to the College, Mr. Clift found it attached to a Placental Ovum, containing a perfect fœtus of the proper size at four months and a half, with an umbilical cord nine inches long. The attachment of the two or twin Ova, was by a spot not larger than a shilling, which is still visible on the smaller or diaphanous Ovum, and was of a bright red colour at the time of separating the two Ova for the purpose of making a distinct preparation of the more complete Ovum, marked in the museum 3448 A.
It appears that the twin Ova were ejected together five months after menstruation.
That the embryo in the smaller Ovum lived is proved by its size as well as by the secreting involucrum having enlarged with fluid to the capacity afore stated. But it did not grow, because unconnected with the mother; while the twin fœtus properly encircled by the placental envelopes, which placed it in immediate communication with its parent, lived as well as acquired growth.
Plate 2
Joseph Perry del et Lithog. Printed by C. Hullmandel.
Dr. Granville on Abortion
and the Diseases of Menstruation