131 



kill a sheep to find out wliat the trouble is, he will subsequently learn 

 that a little loss in the beginning leads to a great saving in the end, and 

 therefore becomes an investnaent. 



In fluke disease not one or two lambs only are infected, bnt all the 

 flock that have been feeding together. If the flock-master has a micro- 

 scope he can detect eggs of tlie fluke in the droppings, but this can only 

 be found after the fluke has matured and the disease has well advanced. 

 Besides, it requires some skill to make the required examination. So 

 numerous are the eggs and so characteristic is the shell with its little 

 cai), however, that this method forms an important element in diagno- 

 sis. The droppings should be moistened with water and thoroughly 

 picked to pieces, then spread evenly on a piece of glass and covered by 

 another thin glass. The mass should be closely examined with the aid 

 of a microscope magnifying from 70 to 80 diameters. This operation 

 should be repeated a number of times if eggs are not found. The ex- 

 amination of the liver is the best means of diagnosis. When the gall 

 ducts are cut open the yonng flakes will be found in them. They usu- 

 ally occur in smaller or larger nodular swellings. The structure of the 

 liver is also characteristic, presenting a dark, soft, rotten appearance. 

 Young flukes can be found by cutting into this organ and washing it in 

 water. After allowing everything to settle, pour off the top and repeat 

 the operation until the contents of the dish can be distinguished. When 

 spread out on aflat-bottomiddish the flukes may be easily distinguished 

 by the unaided eye, or, if very yonng, by the help of a small lens. If 

 the sheep has been killed the flukes will be seen to wriggle and curl, 

 for they die slowly in water ordinarily warm. 



Prognosis. — Tiie disease is very tenacious, and when once on a farm 

 is difBcult to extirpate. Many farms in infected localities are rendered 

 useless for sheep raising by these parasites. When a flock becomes 

 infected it is not to be expected that the disease will be stopped until 

 it has caused extensive damage, and that only the most prompt and 

 eflective measures will save any of the afliicted animals. 



Pathology. — The disease is seated in the liver, and all the symptoms 

 and changes observed in other parts are directly dependent on those 

 occurring in this most important organ. The different periods into 

 which the various alterations have been divided are directly dependent 

 on the periods in the life history of the flukes. For our present purpose, 

 however, it seems advisable to give but the most brief description of 

 these pathologic changes. 



When the flukes first invade the liver they cause an inflammation, 

 which is shown by a thickening of its mass. It becomes softer, and 

 the surface, which should be smooth and glistening, becomes rough. 

 These changes increase as the days go by, and the liver becomes softer ' 

 and thicker. The surface becomes covered by thready fibers, as well 

 as much rougher; the abdomen contains more or less dark-colored 

 serous fluid; young flukes from one-tenth to one-fifth of an inch long 



