Parasites of the Liver. 359 



drew attention to the facts that where the disease formerly scourged 

 the flocks along these rivers it has become comparatively mild, 

 while elsewhere it prevails with all its former fury. Sheep from 

 the western slope of the Cascades exclusive of the Columbia River 

 bottom suffer to the extent of 75 per cent., while on these formerly 

 destructive bottoms but 5 per cent, are infested. The voracious 

 carp eat everything, vegetable and animal, that comes in their 

 way, and while greatly maligned for devouring other fish, they 

 may fairly be claimed as a friend of the farmer in preserving his 

 valuable flocks. The principle is a most valuable one in securing 

 the destruction of dangerous parasites and their invertebrate 

 bearers in the undeveloped larval stage of the former, and we 

 may expect ere long a general culture of frogs and toads in 

 malarial districts to devour the larvas ( ' ' wrigglers " ) of anopheles 

 in breeding swamps and pools. 



Culture of the affected pastures would also accomplish 

 much, as the distomata would perish for lack of the mammalian 

 host. Yet as they can reach maturity in nearly all herbivora and 

 omnivora it would be essential to exclude game and vermin such 

 as deer, antelope, rabbits and hares, in order to good results. 



Avoid drainage water from infested pastures. As in the 

 case of other parasites, extension may follow the water-shed, and 

 hence streams which drain infested land, lakes or ponds, may 

 carry the embryo, the mollusc host, or the cercaria, and are to 

 be carefully avoided. 



Salt marshes and salt licks are destructive to the fluke, but 

 especially to the embryo and cercaria, as well as to the molluscous 

 host and therefore infested sheep or other animals can always be 

 safely turned on such pastures. Perroncito found that a 2 per- 

 cent, solution killed the rediae or encysted cercaria in 5 minutes, 

 and a .64 per cent, solution in less than an hour. 



Sowing salt on infested pastures has been recommended, 

 400 lbs. being applied per acre. This would be especially appli- 

 cable to such low lying swamps as cannot be drained. 



Feeding salt daily to each sheep is another resort. Mix 

 3 lbs. salt with 200 lbs. ground oats and give to each sheep Y^ lb. 

 of the mixture daily. The salt further stimulates digestion and 

 assimilation. In Egypt saltwort (salsola kali) pastures are alike 

 preventive and curative. 



