INSECT.S INFESTING DOMESTIC ANIMALS. 357 



stage. Then the yellow moisture evaporates, giving place to 

 a yellow scab which adheres firnil^^ to the skin and wool.' 

 Raw places appear at points which the animal can reach with 

 its teeth and hind feet. The disease is aggravated in Summer 

 by the presence of the larvae of the blow-fly, the maggot bur- 

 rowing into the scab." 

 Remedy. — Use No. 92. 



CHAPTER CCXLIX. 



The Liver Fluke. (Cal.) 

 ( Distoin a hepaticum. ) 



The following is taken from the Seventeenth Illinois Report, 

 by Professor Cyrus Thomas : 



" Of the intestinal worms that attack sheep, we notice as the 

 most important the Liver Fluke (Distoma hepaticum). This 

 species belongs to the class Scolecida, order Tremoloda or ' Suc- 

 torial worms,' as given above, inhabits the gall-bladder or 

 ducts of the liver in sheep and, it is believed, causes the disease 

 known as the 'rot.' It derives its common name from its re- 

 semblance in form to the flounder, of which ' fluke ' is a Scotch 

 and old English name. It is somewhat broad and flattened, 

 of an elongate-ovate form, somcAvhat pointed at each end and is 

 usually nearly an inch long, often much less, but occasionally 

 more ; its breadth at the widest part, which is toward the 

 front, is about half its length. Its color is usually that of the 

 organ in which it resides. It belongs to a very low type of be- 

 ings, having neither eyes, true respiratory organs, heart, or any 

 other organ of special sense. The sexes are not even distinct 

 and the alimentary canal does not even pass through the body, 

 but dividing and sub-dividing, permeates all parts of it, dis- 

 tributing the imbibed nourishment, which needs little or no 

 assimilation to adapt it to use in forming the materials of the 

 body. It is proper to state, however, that Youatt and other 

 writers on sheep distinctly aflfirm that flukes have eyes and 

 even figure them. But what possible use they have for these 

 organs, in the situation they occupy, it is impossible to say ; 



