llegar states that the changes in the decidua may affect all parts of it, and that one may find, successively: Atrophy, which is not serious, except when it affects the decidua re flexa and the serotina, for simple atrophy of the decidua vem has no harm ful result. Mailer calls attention to the fact that the external surface of the ovum is often thickened, but smooth. Now, detachment of the de cidua in the first half of pregnancy cannot take place without numerous lacerations which give a spongy, rough aspect to the detached surface, the uterine surface being thickened while the fcetal surface preserves a soft and spongy look. Now, in certain abortions, the two surfaces are alike, being formed of a friable tissue. The glandular spaces are widened and, later, there is fatty degeneration. There is atrophy and deficiency of the decidua reflexa, which may also affect the serotina. In this case, says Spiegelbeig, the ovum is in contact with only a small part of the uterine surface and we find the serotina notably elongated, as it were pediculated, and invaginated into the decidua reflexa (Fig. 20). ln the latter, the ovum is sustained by the uterine wall. It may then become detached either by its own weight or by uterine contractions.
If the decidua reflexa is originally lacking, tbe villi of the chorion pro liferate over the whole area of the decidua vera, and then we may have either the placenta spread out, or, as the uterine development is not reg ular, a placenta prwvia. Arrest of development in the decidua reflexa, or its premature destruction, is more frequent. The ovum is then only covered by the chorion and is suspended to a pedicle of the serotina. The pedicle may be elongated, producing cervical pregnancy (Rokitunsky). llegar also mentions hypertrophy, which may affect either the glandular tissue (with cyst-formation) or the interstitial tissue. Finally, there may be congestions in the deeidua, with hemorrhages, as reported by Devilliers, Jacquemier, etc. They are seated, at the same time, on the external sur face, the internal surface, and in the thickness of the mucous membrane, as well in the decidua vera as in tho reflexa and in the serotina.
Scanzoni assumes a communication between the two surfaees through the widened glandular orifices. The same may occur between the decidua reflexa and the cborion. When they are seated in the serotina they ex tend between the reflexa and the chorion, then invaginate the chorion ancl amnion into the cavity of the ovum, and the tutus dies from com pression, unless it was dead before. Sometimes, even the cavity of the ovum bursts and the blood penetrates into the amniotic cavity. If the ovum does not burst, the amniotic fluid is reabsorbed after the death of the fcetus, which is macerated and disappears. The only remnant of the
ovum is debris of the Innis. This is Montgomery's false germ, ova two months old. If the ovum bursts, the fcetus may be expelled without one's knowing it, and then the clots and membranes are expelled later. If expulsion is long delayed, the clot may become more solid, undergo the changes usual in effused blood and be expelled, later, as the so-called. carnified mole. The decidua is often thickened, hypertrophied and very adherent to the uterine wall. This accounts for the long sojourn in utero of the carnified mole, which may undergo pigmentary and other changes. When the chorion and the amnion, or the amnion alone, after rupture of the chorion, have been thus dilated by the extravasation, they form what is called hemorrhagic cysts (Fig. 21),which enclose a sero-sanguinolent fluid or a clear fluid colored and derived from the blood serum. Carnified moles are usually expelled at the fifth month and rarely are larger than an orange. Sometimes part of the mole reraains in utero and may become the origin of fibrous polypi.
We thus see that, although inflammation of the maternal placenta is to-day undoubted, the same is not true of fcetal placentitis. Cauwen berglie regards it as doubtful; Duchamp admits its' existence, with the reservation that, although the suppurative form is doubtful, the chronic or sclerotic form is real. It shows itself in fibrous degeneration of the villi. The cases of so-called abscess of the placenta, numbering ten in scientific literature, are questionable, for not one of the authors remem bered to analyze the pus, and it is more than probable that it was not genuine pus but what Robin has called pseudo-fibrinous pus.
2. Changes in the Chorion.
The maternal placenta is formed by the decidua serotina. The fcetal placenta is formed by the villi of the chorion which, having originally covered the entire surface of the ovum, atrophy over the major part of the surface, while they ramify and develop, ad infinitutn, at the point corresponding to the serotina, where they become imbedded and consti tute the vascular mass known as the placenta. To study changes in the chorion amounts t,o studying the lesio. ns of the placenta and the reverse. Now, these changes may relate to each of the placental elements, i.e., the vessels and the villi. Let us successively study these lesions.
I. Atrophy of the Vial of the Chorion.
This atrophy occurs, normally, in all the villi not destined to form the placenta, i.e., in all not in contact with the serotina, and these villi may pre,sent three different conditions: 1. They are vascular.