Parasites of the Liver. 345 



should also be kept corraled until the dew is off the vegetation 

 together with the invertebrates that are probably infested. 



Then, too, the drinking water must be furnished, not from 

 running streams, which may bring down the embryo or proscolex 

 from higher levels that may be infested by the parasite, but 

 rather from closed and cemented wells into which no surface 

 drainage nor small infested invertebrate can enter. The water is 

 best furnished in troughs set above the level of the adjacent soil, 

 so that it may not become contaminated by drainage, or by in- 

 vertebrate hosts. Such troughs should be occasionally emptied 

 and cleansed, and enough salt should be placed in them at fre- 

 quent intervals to keep the water moderately impregnated. Salt 

 is inimical to most verminous parasites, and the proscolex and its 

 fresh water invertebrate host placed in a saline liquid are likely to 

 perish before being taken in by the lamb, or later in its stomach 

 or duodenum. 



Great care should be taken to fence in or in some way exclude 

 the sheep from ponds of stagnant water which receive the drain- 

 age of surrounding sheep pastures. 



Less important than the above, though still very valuable, are 

 all measures for maintaining the general health of the lambs and 

 thereby enabling them to survive the weakening effects of the 

 parasites. Artificial feeding during periods of drought and of 

 barej)asturage, and especially in autumn and winter, must not 

 be forgotten. Hay from meadows free from the parasite, and not 

 used the previous season for a sheep pasture, may be fed from 

 racks — never from the ground. Grain fed from clean troughs— 

 never from the ground — is of still greater value. 



Protection against cold rain and wind storms, by sheds or even 

 close wind-breaks, will do much to maintain vigor and condition. 

 Finally daily doses of copperas during the trying period may 

 often serve to maintain the balance of health. If the grain and 

 water can be supplied in iron troughs they may at once fnrnish 

 a daily calybeate tonic, and avoid the probability of their harbor- 

 ing the cyst-infested invertebrates. 



But one more suggestion need be made. In seeking for the 

 host of the cystic parasite, no one seems to have investigated the 

 question of its possible presence in the external parasites of the 

 sheep. Yet the presence of the larva of the taenia canina in the 



