There can be no difficulty in understanding how this curious formation came about. The Ovum with its cortex adhered to the ceiling (fundus) of the womb, and contracted an intimate connexion with that organ through its caducous lining. During the first weeks, that external covering, cortex, or membrane, became fleshy and vascular. Plethora took place in consequence, as we have seen in some of the preceding cases of abortion; but, instead of an increased secretion of amnionic fluid, as was the case in the Ova denudata, or diaphanous, of Plate I., the effect has been a dropsical bead-like enlargement of the mossy or filiform vessels of the Ovum. In proportion as these advanced and enlarged, they detached and forced outwardly the coriaceous envelopes, which began to absorb at their inferior edges in that irregular progression which left them as they are now seen, irregularly echancrés. This process of absorption in the outer envelopes of the Ovum, from the first to the fifth month, is what takes place generally, even when they are not morbidly affected in their texture in the way in which they are in the present instance, and is the process by which the placenta is formed. But in order to effect this properly, the mossy or filiform vessels, of nearly three fourths of the circumference of the young Ovum should also become progressively obliterated; while those which remain, mingling with the superimposed envelopes, swell into large blood vessels to assist in the formation of the placenta. Here, however, such a process was impossible, inasmuch as the mossy or filiform vessels, having taken up a morbid action and become distended with the serosity, which kept constantly pouring into them, could not become absorbed to the extent required to form the placental cake, but on the contrary continued to increase in size and number. This operation took place at the expense of the growth and life of the embryo, which is consequently seen to be stinted and undeveloped. Abortion, therefore, was inevitable sooner or later.
The specimen is also valuable, as it affords positive evidence of the mode in which the placenta is formed, for here we actually see the process of absorption of part of the involucra, on which that process depends.
Some who have seen this specimen, confound it with a case of hydatous placenta; and a few similar preparations exist under that name in more than one collection. It is evidently by mistake that they are so styled, as we shall see in a succeeding Plate.
Professor Carus of Dresden, (a name revered by anatomists and physiologists,) here comes to my assistance. That accurate and indefatigable observer, on submitting an entire Ovum, expelled towards the sixth week of gestation, to a powerful microscope, remarked that the greater number of the filiform vessels were diaphanous as well as their ramifications, and that their free extremities terminated into little roundish knobs, not unlike the terminal bulbs of the villosities of the intestines. These bulbous expansions of the filiform vessels of the Ovum adhered so firmly to a superincumbent dense membrane (which Carus calls decidua, but must be the cortex) that they could not be separated from it without tearing some of them[[27]]. These very expansions, or roundish knobs then, of the filiform vessels of the Ovum, are precisely those which, from plethora of the involucra lying over them, acquired what, in my specimen, I have called “a dropsical bead-like enlargement,” as represented in figure 17 of an “Uviform Ovum.” Soemmering has also noticed these terminal bulbs of the filiform vessels, which he calls noduli vel vesiculæ, somewhat like hydatids.
In questions of natural history, it is impossible to desire and meet with a more satisfactory corroboration of the explanation of any given fact, than the above observation of Carus affords to my view of the conformation of the “Uviform Ovum.” Nor can a more convincing refutation be required after it, of the doctrine of hydatids in the placenta being the cause of that singular conformation.
There was but a trifling hemorrhage after the coming away of the present Ovum, and scarcely any suffering. During the three preceding weeks the patient had had some slight, colourless, and thin discharge from the vagina.
Plate 5
Joseph Perry del et Lithog. Printed by C. Hullmandel.
Dr. Granville on Abortion
and the Diseases of Menstruation