PARASITIC DISEASES. 157 



Depending on the severity of the infection, the 

 disease progresses until the animal never seems 

 to be at rest. It becomes thin; the wool falls 

 out in patches usually along the flanks and back; 

 larger and larger areas of the skin become in- 

 flamed and covered with crusts ; others become in- 

 fected, and soon the whole band is one rubbing, 

 biting, scratching mass of distracted sheep. 



Differential diagnosis: Practically the only 

 way to become familiar with the disease is to 

 see a genuine case. After this, the rest is com- 

 paratively easy. 



Wool that has fallen out due to "blue bag" in 

 ewes, or to exposures, leaves a soft, normal skin. 

 There is nothing but a ' ' bald spot ' ' with no pim- 

 ples, vesicles, papules or inflammatory zones. 



Eczema of the various types merely shows a 

 reddening of the skin without the thickening that 

 accompanies ' ' scab. ' ' 



In sheep work it is always safe to think of scab 

 first, in suspicious cases, and to act accordingly. 

 This will protect the veterinarian and the owner, 

 even if it does put the latter to a little incon- 

 venience. 



Treatment: As is well known, dipping and 

 quarantine have nearly eradicated this disease 

 from our country. The subject of quarantines 

 has been taken up in the section on Federal and 

 State regulations. 



Dipping with "lime-and-sulphur" has been the 

 mainstay on the western range, the official dip 

 being prepared as follows : 



