DURATION OF HYDATID GESTATION.
Dubois and Desormeaux describe three varieties of hydatid mole: 1st. The embryonal hydatid mole. 2d. The hollow hydatid mole. 3d. The hydatid mole en mane.
The first variety consists of a membrane, vesicular on its outer surface, with an internal cavity containing a fcetus or parts of one, and possibly fluid.
The second kind is like the first, save that its cavity contains only fluid, and possibly a remnant of the umbilical cord, the fcetus having been dis solved.
The third variety is distinguished by the enormous development of the hydatid bodies, and the more or less complete effacement of the central cavity formed by the amnion, the place of which is taken by a mass of soft, yellowish, spongy tissue.
Moles of all kinds are covered by a thick membrane, which is in imme diate contact with the uterus, and which is nothing but the decidua.
Cayla has sought to prove that the hydatid moles are only uterine vil losities, modified in shape and size by the accumulation of fluid within their cavities. Ile thus describes what he calls dropsy of the chorional " The pedidle of the villus forms a membranous tube filled with serosity, and some to one inch in length. At the point where the pedi cle begins to branch, the dilatations or hydatid vesicles begin to develop. They may be as large as a hazel-nut, or so small as to be hardly visible, smaller vesicles often springing by a short pedicle from the larger ones; the pedicle being the non-dilated portion of the branch. The flow of fluid is free from one vesicle into another. Curious groups of vesicles of varying size and shape are thus formed. Each vesicle is oval, spheri cal or pear-shaped. Occasionally one will be found triangular, or even cylindrical in shape. A few are more irregular, and have prolongations in various directions. The microscope shows small cysts upon the pedi cles or on the walls of the vesicles; these are vesicles in process of forma tion.
Texture of the Hydatid Bunehes.—They are usually easily isolated, though they may be more or less intimately interlaced, when they ,form a masa of cysts 98 thick as the placenta, in the centre of which nearly nor mal villi may be found.
"Contents of the Vesieles.—The walls are thin, semi-transparent and resisting. The contents consist of a transparent, reddish, serous fluid, albuminous and coagulable by alcohol and nitric acid. There is no trace of cysticerci or echinococci.
" Two varieties of special cells were found in equal and limited numbers in this fluid.
"The first are spherical, transparent and regular with one or two round nuclei, and contain fine gray molecular granulations. The nuclei con tain a small brilliant nucleolus. They are unlike any known anatomi cal element.
" The second variety belongs to the class of pavement. epithelium and are exactly like the cells of that tissue save for the brilliant, yellowish, molecular granulations that they contain. It is difficult to understand the origin of these cells if we admit that the cysts were formed after the penetration of the vessels; for there is no pavement epithelium in capil laries.
" The walls of the vesicles are formed by the chorional tissue. They contain a large number of brilliant molecular granules, or sometimes, in stead of that, very fine grayish grains. Thus the hydatid vesicles are nothing but dilatations of the chorional villi." We have seen that the diopsy may occur when the placenta is com pletely organized, but that it may take plae,e much earlier is shown by the isolated vesicles, and by the examples of eggs expelled entire, whose whole chorional surface was covered with groups of vesicles, proving that the alteration occurred at a time when the chorion was entirely vinous.
Clots of varying consistency and color are almost invariably found in the midst of the vesicular mass, which may explain the coloration of the vesicles. Amnion and chorion showed no lesion. The weight varies, and may reach eleven pounds.