186 PREVENTION AND TEEATMENT OF SCABIES. 



sheep's backs, and to fix in the fleeces materials which should 

 not be washed out with the first shower of rain. These active 

 principles are mixed with various kinds of solid fats, oils, and 

 soaps. It so happens, however, that many of the active 

 principles injure the sheep and the wool; whereas the fats 

 and oils are apt either to destroy the colour of the fleeces, or 

 so mat them together as to render them dangerous to the sheep, 

 and prevent the clips realising a fair price in the market. 



An examination of many fleeces smeared with all kinds of 

 material has led us to notice, that farmers have been much 

 misled in being induced to use the compounds hitherto offered 

 them ; and when we consider that, in addition to the eight- 

 pence or tenpence which it costs them to smear the sheep, 

 they lose from one to several shillings per fleece when their 

 flocks are shorn. It is evident that the question is one of the 

 greatest economic importance to the flock-masters of the 

 United Kingdom. We shall first notice the active principles 

 used, and, in the next place, the materials with which these 

 principles are mixed. 



Active principles. Mineral poisons, such as mercury, in 

 the state of oxide or as corrosive sublimate, and arsenic, have 

 been often condemned. We have only to repeat that they 

 should never be used. Many of the advertised dipping com- 

 positions should not be applied without first sending them 

 to a chemist, and if found to contain any of the above or 

 other mineral poison calculated to kill the sheep or other 

 farm stock, they should be returned to the vendor. 



Common or Venice turpentine, white tar, as some call it, 

 is used largely with mercury and in combination with other 

 materials. It does not kill the sheep, but it deteriorates the 

 value of the fleece. We have seen many fleeces treated with 

 this substance which could not be sold at even a moderate 

 price, in consequence of the manner in which the wool was 



