THE CIRCULATORY SYSTEM. 145 



in the structure of the heart, or in some organ which 

 does not form a part of the circulatory system. 



Hydatids which are developed in the substance 

 of the heart may acquire a considerable size before 

 they give rise to any evident derangement in the 

 fimctions of that organ ; in some cases, they do not 

 produce any appreciable phenomena until the cyst is 

 ruptured, and its contents are poured out into the 

 cardiac cavities ; the vesicles, either whole or broken 

 into pieces, are carried into the vessels with the 

 blood, and present such obstacles to the due perform- 

 ance of the circulation as to produce immediate 

 complications, and occasionally sudden death. 



This latter termination, without any premonitory 

 symptoms, has been known to occur when the hydatid 

 cyst in the heart was unbroken. 



There is no sign which can be considered as 

 diagnostic of the existence of vesicular worms in the 

 heart. 



Hydatids which are developed in an organ which 

 does not form a part of the circulatory system, may 

 produce perforation of the blood-vessels with which 

 the cyst is in relation ; the result of this perforation 

 is the introduction of the fluid contained in the cyst, 

 of atheromatous matter, and of the vesicles them- 

 selves or of their fragments, into the vessels. 



The introduction of the contents of an hydatid 

 cyst into the current of the circulation must neces- 

 sarily lead to serious derangements, which are of 

 varied intensity, in proportion to the size of the 

 perforation, and to the quantity and condition of the 

 fluid which is admixed with the blood. 



The bile itself may, in cases of hydatids of the 



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