The tendency to rupture of the cyst-wall is one of the characteristics of this form of tumor. The wall becomes weakened by atrophy or fatty degeneration, or by direct pressure of the luxuriant papillary growths. These growths make their way to the outer surface of the cyst, and extend thence throughout the peritoneum; or, if rupture takes place, the cyst may become so inverted that the site of each ovary is occupied by a mass of papillomata; the formerly enclosing cyst has disappeared, and its remains can be discovered only by careful dissection (Fig. 169). Such a condition has undoubtedly often been mistaken for primary papilloma of the ovary, the real origin in a papillomatous cyst not having been detected. The secondary affection of the peritoneum is due not only to continuity of tissue, but to implantation and growth of portions of papillomata that have become broken off and carried to different parts of the peritoneal cavity. Such secondary growths may extend throughout the whole abdomen from the pelvis to the diaphragm, covering any of the viscera. They resemble in all respects the original papillomata found in the interior of the ovarian cyst. They sometimes form cauliflower-like masses as large as the fist, and may be palpated through the abdominal wall. They are very vascular, and bleed profusely on being handled. The smallest particles of papillomata are capable of infecting the peritoneum or other tissues in this way. [Illustration: FIG. 169.--Double papillomatous cyst of the ovary. The right cyst has ruptured and is turned inside out, showing a mass of papillomata. Papillomata have penetrated the wall of the left cyst. The peritoneum has been infected, and a papillomatous growth appears on the fundus uteri.] The escape of a small quantity of the cyst-fluid into the abdomen during the removal of the tumor may cause subsequent recurrence in the peritoneum. Secondary development of the growth in the abdominal cicatrix, or its appearance in the site of puncture after tapping, is due to the same cause. Papillomata of the peritoneum are usually accompanied by ascites. This is a prominent symptom in those cases of papillomatous ovarian cyst in which secondary infection of the peritoneum has taken place. In rare cases ascites is present, though perforation of the cyst and involvement of the peritoneum cannot be detected. Sometimes perforation of the cyst takes place into adjacent organs, especially if the growth be intra-ligamentous. In such cases the papillomatous masses may protrude into the bladder, the rectum, or the cavity of the uterus. CHAPTER XXX. CYSTS OF THE PAROVARIUM. The parovarium consists of a series of fine tubules lying between the layers of the mesosalpinx. It may be seen in the fresh specimen by holding the mesosalpinx stretched between the eye and the light (Fig. 145).