288 



DISEASES OF THE LIVER. 



the liver and to puncture and evacuate the contents of some of the 

 cysts; but the result would be illusory, because some vesicles would 

 always be inaccessible, and economically intervention would be nicomplete 

 and useless. 



Although there is no useful method of treatment, prophylaxis is 

 possible and valuable. It consists in preventing the development of 

 tffnia3 in farm and sporting dogs. For this purpose it is sufficient to 

 pre^•ent their obtaining raw offal containing vesicles of echinococci from 

 sheep, oxen, or pigs, and also to free them from any helminths which 

 they may harbour. In this way they no longer spread eggs of tajnife 



Fig. 133. — Pig's liver with echinoooccus cysts. (After Eailliet.) 



with their fteces in the neighbourhood of ponds or drinking places, and 

 the cattle do not ingest the embryos. 



SUPPURATIVE ECHINOCOCCOSIS. 



Causation. Simple echinococcosis may remain undetected for a long 

 time, and young animals affected with it may grow up without exhibiting 

 marked general disturbance. The old echinococci end by degenerating, 

 the wall of the cyst becomes modified, the liquid it contains, turbid, 

 lactescent, then caseous ; the vesicle becomes wrinkled, and finally 

 nothing resembling the primary vesicle remains. The liquid is soon 

 absorbed, and the primary cyst is only represented by a caseous magma, 

 which undergoes calcareous infiltration and progressive atrophy. 



Under other circumstances the development of the echinococcus 



