INSECTS AFFECTING MAN AND ANIMALS 205 



rubbed. The most common source of infection is securing 

 sheep from stock yards. It is well, therefore, always to dip 

 sheep as soon as received. 



The same dips as recommended for the sheep ticks will be 

 satisfactory if used according to directions, and one dipping 

 will kill both, as well as sheep lice. The tobacco dip should 

 contain at least seven one-hundredths of 1 per cent of 



FIG. 146. The sheep in the middle of the group is affected with a 

 slightly advanced case of sheep scab, as is seen by the tufted wool 

 and bare spots on fore flank and crops. The other two sheep 

 represent advanced stages of the disease. (Ky. Agr. Exp. Station.) 



nicotine when used. A nicotine-and-sulphur dip containing 

 not less than 5/100 of 1 per cent nicotine and 2 per cent 

 sulphur has been proven satisfactory in extensive tests. 

 The dipping should be repeated in ten or twelve days to 

 kill the mites hatched since the first dipping. It is best to 

 have the dip warm, about 100 to 105 Fahrenheit. If 

 scabby sheep are taken from buildings, the buildings should 

 be disinfected before returning healthy sheep to them. Pas- 



