DISEASES DUE TO INTERNAL PAEASITES. 231 



of the abdominal sucker, always recnrved. Vulva small, situ- 

 ated at the side of the male orifice or a little behind. Eggs 

 brown or greenish, ovoid, length from 0.130 to 0.145 mm., width 

 0.070 to 0.090 mm." 



The parasite has been found in the livers of the sheep, 

 goats, cattle, camels, and a number of wild ruminants, also in the 

 horse, ass, pig, elephant, rabbit, and man. Its habitat is in the 

 biliary ducts of the liver where, according to Kuchenmeister, it 

 feeds on the blood from the mucous membranes of those pass- 

 ages. 



Its life history was first determined by Leuckart, and later, 

 but independently, by Thomas, an English scientist. 



It was called the fasciola hepaticum by Linnaeus, the 

 naturalist, the name of distoma hepaticum being bestowed on it 

 by Eetzius, the word hepaticum being used in conjunction with 

 either of the others to designate that the fluke is found in the 

 liver. 



The flukes deposit their eggs in the biliary ducts, from 

 which they pass into the intestines, and are voided from the sys- 

 tem, dropping on the ground, where those falling in suitable 

 places, under favorable conditions, hatch and escape by the rais- 

 ing of a lid-like contrivance on the small end of the egg. These 

 newly-hatched parasites are not young flukes; on the contrary, 

 they are small ciliated embryos, which are enabled by the fine 

 cilia (hair) covering them to swim about in water. These em- 

 bryos immediately seek out the small water snail, it being neces- 

 sary for the completion of the life cycle of this remarkable para- 

 site that this snail act as an intermediary host for it during the 

 completion of this stage. Should the embryo fail to become 

 .attached to the Avater sn^ail in two days time it will die without 

 ■completing its life cycle. On the other hand, should it become 

 ■attached to the snail, it immediately bores through the shell. 



