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XLII] bodies of the females is embedded in the connective stroma; consequently they cannot be extracted unless in fragments. The males lie in the little cyst-like cavities in the tumours, and can be turned out entire. The posterior extremity of the male with its copulating organs, and the anterior extremity of the female with its vaginal opening, are free and contiguous in one of the spaces. The formation of the tumours is elucidated by Labadie-Lagrave and Deguy's case. These authors found an immature female ''0. volvulus'' in a lymphatic vessel partly obstructed by an infiltration of fibrin and leucocytes. It appears, therefore, that the presence of the parasites within the lymphatics gives rise to an inflammatory process, and that the consequent fibrinous deposit envelops the parasites, obliterates the lumen of the vessel, and ultimately isolates the affected tract. According to the natives, the tumours may last indefinitely, and they seldom ulcerate or suppurate.* Some old patients told Brumpt that their tumours had been present since childhood. (See Juxta-articular Nodules, p. 919.)

Ouzilleau concludes from some remarkable but unconfirmed observations that in the Mbomou region, Equatorial Africa, where F. bancrofti is absent or very rare, but elephantiasis, lymphocele, and lymph-scrotum very common, ''0. volvulus'' is the cause of these diseases in that district. Microfilaria volvulus, he states, is invariably present in the enlarged inguino-crural glands.

Life-history.— Nothing is known of the life-history of this filaria. Recently, larvæ, presumably those of ''0. volvulus'', have been found in the peripheral circulation by Fülleborn, Simon, Ouzilleau, and Rodenwaldt. Brumpt, from the examination of numerous sections of filarial tumours, is confident that the microfilariæ leave the cysts. He has seen them round the periphery of the tumours, and believes they may reach the lymphatics and thence the general circulation. He even suggests that the infection is