HYDATID TUMOURS. 133 



Chapter XVIII. 



The usual Seats op Hydatid Tumours. — The Cibcumstances 



WHICH regulate THEIK DEVELOPMENT AND FbEQUENCT. — 



The Changes in neighbouring Organs, produced by 



THEIR PRESENCE. — ThE DIAGNOSIS, PROGNOSIS, AND ORDI- 

 NARY Termination of Hydatid Tumours. 



Hydatids are found in all of the parencliymatous 

 viscera in Man, although with a very different degree 

 of frequency; the liver alone furnishes more cases 

 than all of the other organs taken together. When 

 hydatids do exist in some distant parte of the body, 

 they may often be, at the same time, met with in the 

 liver ; next to this organ come the lungs, in respect 

 to the frequency of hydatids ; vesicular tumours are 

 also occasionally present in the spleen, the kidneys, 

 the omentum, and the brain ; some few examples 

 have been recorded in the spiaal cord, the eye, and 

 even in bones ; hydatids are seldom seen in the 

 extremities or in the parietes of the chest and of the 

 abdomen ; the testicle, the uterus, and the mammae 

 are very rarely affected by them. 



The hydatid cyst is often single, but it is not, 

 however, unusual to see two, three, or four cysts in 

 the same organ, or in various regions of the body ; 

 their number seldom exceeds ten or twelve, although, 

 in some instances, more than fifty and even as many 

 as a thousand, have been observed. 



The tissues or the viscera in which hydatid cysts 

 are developed may remain for a long time without 

 experiencing any appreciable change. At a subse- 

 quent period, however, they often become more or 



