FASCIOLA HEPATICA. 169 



the embryo of Fasciola hepatica undergoes are not clearly defined. 

 Moulinie and otliers have referred to certain of the Cercari^, and 

 the higher forms of trematode larvse as the young of our fluke, but 

 it cannot yet be positively asserted that we know the higher larval 

 conditions of this parasite. Undoubtedly, we may, by inference, 

 form a tolerably accurate notion of the ulterior changes which our 

 embryo undergoes before it arrives at the true distome-type of 

 structure ; but in doing this we can only form our general conclu- 

 sions from data furnished by the history of the development of 

 other well-known species. The course of development usually pur- 

 sued has already been illustrated in the case of Distoma militare in 

 the early part of this work (pp. 23 — 32), where I have also recorded 

 Pagenstecher's conclusions in regard to the development of trema- 

 tode larvae in general. At tliis point, therefore, I shall quit the 

 subject of fluke development, only referring to it again when offer- 

 ing a final brief resume of the principal facts bearing upon the 

 origin, development, and destiny of the species under consi- 

 deration. 



Injurious Effects upon Man. — Though of comparatively rare 

 occurrence in the human body, the common liver-fluke is, in an 

 indirect manner, extremely injurious to man. By its prevalence in 

 the lower animals it cuts off" a large supply of healthy food, at the 

 same time producing a quantity of meat unfit for the market, but 

 which, nevertheless, is largely eaten by our poorer inhabitants. 

 Even the odour arising from the diseased condition of the animal's 

 flesh is not without its baneful effects, and in one instance, at least, 

 it appears to have been the immediate cause of death. In the 

 month of August, 1854, says Mr. Simonds, in his admirable trea- 

 tise on the Rot, " a person of intemperate habits, following the 

 occupation of a country butcher, was employed in skinning and 

 dressing a number of rotten sheep on the premises of a farmer in 

 the county of Norfolk. The sheep were necessarily opened when 

 warm, and while he was so engaged, he complained greatly of the 

 sickening smell. The same evening he was attacked with choleraic 



z 



