THE PAROVARIUM.
Syn. Corpus Conicum. Areben-Eierstock. Organ of Rosenmiiller.
These names have been applied at various times to an organ which has hitherto received little attention, but which is nevertheless in variably present in close proximity to the ovary. The first discovery of this body is due to Rosenmilller f, who termed it the corpus conicum. It has since come under the notice of rnany observers, and particularly of J. Miiller. And it has recently been re examined, and very accurately described by Kobelt t, in an essay devoted to this subject, in which the author expresses his surprise that a structure so easily distinguished both by sight and touch, should have attracted comparatively so little attention up to the pre sent time.
The Parovarium is most readily found by holding up the broad ligament between the observer and the light. Within the folds of this membrane, at the part where the layer of peritoneum, after investing the Fallopian tube, passes off towards the ovary, to form the posterior duplicature which encloses the vessels proceeding to that organ, will be found a small plexus of white tortuous tubes, (fig. 403.a, b, c) arranged somewhat in the form of a cone whose apex is directed towards the hilum of the ovary /, and its base a c a to wards the Fallopian tube h. The entire or gan measures about one inch in breadth, and is composed of 2-20 tubules 0.15-0.2"' in diameter.
The tubes which contain nothing but a clear fluid consist of fibrous membrane, lined by a single layer of cylindrical, epithe lial cells. These tubular canals are not known to have any direct communication with the ovary.
That the parovarium is formed out of the Wolffian body does not now appear to admit of doubt. It has been usually considered that the Wolffian bodies are organs peculiar to fcetal life, and that they afterwards entirely disappear in both sexes. Hence no special investigations have been undertaken with a view to ascertain their ultimate fate. Meckel indeed compared them to the epididymis.
Rathke believed that they became epididymis in the male, and disappeared in the female ; while Rosenmiiller, who discovered the paro varium, compared this body to the epididy mis. Some general conjectures also have pointed in the male sex to the vascula aberrantia of the epididymis, and in the female to the or gan of Rosenmilller and the ducts of GHrtner, as the supposed remains of the Wolffian body. Nevertheless it is, according to Kobelt, an undoubted anatomical fact that each pretended ephemeral structure not only exists through the whole of life in both sexes, but that it absolutely increases up to its highest state of perfection, and first suffers a gradual re trogression, after the extinction of the repro ductive function, but never entirely disappears.
The signification and true homologies of this singular organ cannot be understood without first briefly examining the mode of formation and developiagnt of the Wolffian body, and tracing its relation to the genera tive gland and Fallopian tube. In this exa mination it is also of consequence to compare the progressive steps of formation of those parts with the corresponding structures in the male.
The Wolffian body is most readily exa mined in the chick, (figs. 399, 400.) Here during the third day of incubation are formed two canals which extend along the sides of the vertebral column, from the heart to the posterior extremity of the body. To the inner side of each canal is attached a series of blind pouches (fig. 399. c and 400. b), which during the next two days become lengthened and convoluted. These together constitute the Wolffian body. Behind them, and fermed independently at a somewhq later period, lie the kidneys (fig. 399. and 4ZO. a) and supra renal bodies, (fig. 399. f, 400. d) and as these increase, the Wolffian bodies diminish. The testes (fig. 399. e) and ovaria (fig. 400. are developed upon the inner border, and front of the corpora Wolffiana.