HYDATID TUMOURS. 135 



affected organ, and the inflammation extended to 

 distant viscera ; but it is probable that this com- 

 plication only arises subsequently to the accidental 

 conununication of these vessels with the cavity of 

 the cyst. 



In other cases, the parts which are in relation 

 with the hydated pouch are destroyed and ulcerated, 

 as well as the corresponding wall of the pouch, which 

 is thus perforated and affords a means of exit to the 

 matters which it encloses ; the hydatid cyst, under 

 such circumstances, opens directly upon the surface 

 of the body, or into some passage which has a more 

 or less direct communication with the exterior of the 

 body, such as the bronchi, the intestinal canal, the 

 bihary tubes, and the urinary passages, or else into a 

 closed cavity, like the pleura, the peritoneum, or even 

 the veins. In this manner, the tumoiu' is sometimes 

 brought into communication with some distant organ 

 which has ordinarily no connection with that in 

 which the hydatids are contained ; cysts situated in 

 the liver, for instance, after the diaphragm and the 

 pulmonary tissue have been perforated, occasionally 

 open into the bronchi, through which their contents 

 are finally discharged. 



It is not upon the soft parts alone that the pres- 

 sure of hydatids exerts a destructive influence ; for, 

 when they are in relation with a bone, they may give 

 rise to absorption and perforation. Andral relates 

 the case of a patient in whom acephalocysts primarily 

 developed in the sub-scapular fossa, made their way 

 through the shoulder-blade into the sub-spinous fossa. 



A communication may be estabhshed between 

 two hydatid cysts by the perforation of both. The 



