Diseases 283 



with the cost of well-known vermicides, that their 

 use is hardly to be recommended. Moreover, their 

 value is greater as a preventive than as a cure. 

 They retard the development of worms when fed 

 regularly, after the lambs have begun to graze, more 

 effectively than they remove the worms after a 

 serious infection. The invasion of the lambs by all in- 

 ternal parasites commences very soon after they begin 

 grazing with old sheep upon pastures favorable to 

 their transmission. It was formerly thought to be by 

 way of surface water, but it is certain the invasion of 

 lambs may take place upon perfectly dry pastures and 

 in a dry season. Lambs, however, are troubled more 

 in wet years, but because of their lower vitality rather 

 than on account of the greater invasion of parasites. 



Medicines that have proved of value as preven- 

 tives are tobacco, copperas, turpentine, and blue 

 vitriol. The former three may be fed in connection 

 with salt. Use one pound of salt to four pounds of 

 tobacco leaves, equal weights of salt and copperas, 

 or salt saturated with turpentine. These may be 

 kept before the flock all the time. The blue vitriol 

 is best administered in solution, one dram to each 

 sheep. This has proved a valuable remedy in ad- 

 vanced cases of stomach-worm invasion. Gasoline 

 in one- to three-dram doses administered with milk 

 has also proved a valuable remedy. 



The stomach warm. — If any one worm is the 

 cause of more deaths than any other, it is the twisted 



