15 



unless they can obtain the young forms of the parasites by eating the 

 viscera of sheep they would be very unlikely to be infected with adults. 

 It is also reported that rabbits harbor the cystic form of Taenia margin- 

 ata; but this statement has not been corroborated, as the rabits ex- 

 amined contained the cystic form of T. serrata. If rabbits should be 

 proven to harbor the cysts of T. marginata then the danger would 

 arise, not from them, but from hunting-dogs which eat the rabbits and 

 the cysts they contain, and harbor the adult parasites that alone are 

 the source of danger. The possibility of infection by parasites from 

 deer is too small to be considered as an economic question, owing to 

 the great scarcity of these animals. The antelope (Antilocapra ameri- 

 cana, Ord.) may be a bearer of many of the same species of parasites as 

 the shee!p, but they also are becoming too few to be considered as a 

 source of danger. In short, it is futile for the flockmaster to consider 

 these sources at all while his own flocks are infecting his fields, and his 

 dogs are constantly assisting them. Could these sources of infection 

 be controlled, there would be no need for him to regard the wild ani- 

 mals as his enemies. " 



In purchasing sheep particular attention should be paid to the gen- 

 eral appearance and past history of the flock from which the purchase 

 is made in order to avoid parasitic diseases. Before adding recent pur- 

 chases to flocks they should all be thoroughly dipped to kill external 

 parasites.- If they are coughing ever so slightly, the cause of the cough 

 should be investigated to determine the presence or absence of lung 

 worms. If some are hidebound or weak after allowing for the charac- 

 ter of the season and the condition of pasturage the possible presence 

 of intestinal parasites should be next considered. It is not very prob- 

 able that there are any farms free from all parasites, but there are many 

 that are free from a considerable portion of the species which are prop- 

 erly parasitic on sheep. Purchasing here and there in making up a 

 flock brings all sorts of parasites together, thus infecting a farm to such 

 a degree that it is difScult to get rid of them. 



The medical treatment must, of course, be specially adapted to the dis- 

 ease. The treatment of external parasites is effective, and well repays 

 all efforts. The treatment of internal parasites may be divided in gen- 

 eral into treatment for lung worms, for intestinal worms, and for liver 

 worms. The last is by far the most unproductive of good results. Par- 

 asites situated elsewhere in the sheep do not readily yield to medical 

 treatment. 



Scab is the only parasitic disease that has been thought worthy 

 of legislation. There are others that demand as serious considera- 

 tion, but their importance has not yet been fully presented to the 

 public. Little attention has been given to police interference in the 

 management of these diseases. Ko doubt such interference might be 

 profitably pushed further than it is in this country, especially with 

 regard to scab. Not only should the highways be guarded against the 



