Finally, and it is a most important argument, partial myxomata of the placenta occur in children which are well developed, and which have died during the last months of pregnancy.
The lesion of the membranes is then the original one. Does it begin as an initation of one of the uterine surfaces, or does it come by the blood of the mother ? The fact that women sometimes have hydatid moles several times, and that in them the decidua plainly shows traces of inflam matory thickening, and even, according to Virchow, little polypoid excres cences, is favorable to the former view. A more or less extensive endo metritis will cause such hypertrophy of the villi, that each one will form a true, independent tumor, and will not only deprive the embryo of the nutritive materials which they should supply to it, but, wheu that embryo is destroyed, can continue to live and furnish a perfect example of a trne parasitic tumor, heterologous even to the mother's body, and yet proceed ing from it.
The theories concerning the vesicular mole may be summed up, as Duchamp says, in the following propositions: lst. The vesicular mole is entirely independent of pregnancy; 2d. The vesicular mole increases under the influence of pregnancy, but is not due to disease of the egg; 3d. The vesicular mole is due to a change in the product of conception, from—a. Alteration of the vascular walls (Cruveilhier); b. Alteration of the lymphatic vessels; c. Dropsy of the ehorional villi (Robin. Cayla); d. Myxomatous degeneration (Virchow and the Germans, Erco lani, Damaschino, Cornil, Ranvier, Hirtzmann, 1874, Josephson, 1879).
The vascular and lymphatic theories are untenable, and if true hydatids have been expelled from the uteri even of virgins, they bore no likeness to the clusters of the vesicular mole.
Ancelet's idea, that it is a disease of the decidua, is wrong, since the degenerated villi might contract adhesions to the decidua without that membrane being affected; besides which the villosities have been seen to be continuous, by their pedicles, with the chorion.
Ruysch and Cruveilhier's vascular theory is disproved by the fact that the vessels are not dilated, but obliterated; and the theory of the lym phatics is in complete opposition to the structure of the villi.
There remain the two theories of Robin and of Virchow. Both place the morbid change in the villi, but Robin claims that the vesicle contains nothing but a fluid, in which a few cells float freely, while Virchow holds that what fluid there is, is simply the intercellular fluid of a tissue. The following reasons favor the latter opinion: 1st. The normal villus con tains mucoid tissue; it is not astonishing that it should hypertrophy; 2d. The vesicular fluid contains mucin; the following is Gscheidlen's analysis: Chloride of sodium, . 3. 34 Phosphoric acid, . O. 74 Albumin, . 6.12 Mucin, . 2.94 Salts, . 6.25 • • • • 3d. Virchow, Cornil, Ranvier, Malassez and de Sinety, have demon strated the identity of the vesicular mole with myxomata of other regions.
vesicular mole is rare, and is found oftenest in multiparte of twenty-five to forty years. A molar pregnancy is apparently, to a cer tain extent, a predisposing cause. As to its etiology, Ruysch, Scanzoni and Graily Hewitt, find it in the death of the fcetus; but moles have been found with living children. Virchow attributes it to endometritis, and this is the generally received opinion in Germany to-day. It is prob able that the myxomatous lesion begins in the abundant mucoid tissue of the villosities, and that this tissue becomes infiltrated with fluid.
to Depaul three symptoms are generally found; but they may be ;wanting, in part at least: 1st. Rapid and exaggerated development of the abdomen not in accordance with the period of preg nancy (Boivin, Depaul); 2d. Small and frequent hemorrhages of a peculiar character. According to Percy, there is an alternation of small hemorrhagic and watery flows, commencing in most women at the second month, and continuing at longer or shorter intervals until parturition. Gardien observes that the expulsion of hydatids is usually accompanied by hemorrhages and syncopes, and Depaul has observed tho same pecu liarity; 3d. The expulsion of clusters of vesicles, or of isolated ones.