tJiSTOMATO.SIS— LIVES FLUKK DISEASE— LIVER KOl\ 293 



animals infested with Cii^ircrciis tniuicolUs are nothing more nor less 

 than these tubes, or altered blood-vessels, caused by the growth and 

 wandering of the parasites. 



Curtice takes a somewhat different view— that is, he considers the 

 Hver as a place of destruction for the young parasites, rather than a 

 normal place for their development; he also claims that the embryos, 

 which may even travel the entire length of the intestine of the inter- 

 mediate host, traverse the intestine and arrive directly in the position 

 where they complete their larval development without first passing 

 through the liver. 



After developing into the full-grown bladder worm, the parasites 

 remain unchanged until they are devoured by a dog or wolf, or until, 



Fig. 141. — Cross-section of the liver of a lamb which died nine days after feeding with 

 eggs of the niargmate tapeworm [Tcoiia marginata). (After Curtis.) 



after an undetermined length of time, they become disintegrated and 

 more or less calcified. 



If the hydatid is devoured by a dog or wolf, either when the latter 

 prey upon the secondary host or when the dog obtains the cyst at a 

 slaughter-house, the bladder i^ortion is destroyed, the scolex alone 

 remaining intact in the digestive fluids. The head holds fast to the 

 intestinal wall with its suckers and hooks ; by strobilation (transverse 

 division) it gives rise to the segments, which as we have already seen, 

 together with the head, go to make up the adult tapeworm. Eepro- 

 ductive organs of both sexes develop in the separate segments, and 

 eggs are produced, within which are developed the six-hooked embryos, 

 the point from which we started. 



DISTOMATOSIS -LIVER FLUKE DISEASE- LIVER ROT. 



In France the name of distomatosis has been given to a disease caused 

 by the presence of distomata in the bile ducts. It is the " liver rot " of 

 England, the Eberfaule of Germany, and is produced by the growth in 



