SAND COLIC. 195 



furnishing favorable conditions for the parasites, and because tlie 

 sheep are kept in closer contact at these seasons. The disease 

 makes more rapid progress and is much more fatal with the weak- 

 er sheep. These parasites may be transferred from one sheep to 

 another in a great variety of ways ; for instance, tags of wool may 

 be rubbed off and dropped almost anywhere. Diseased sheep in- 

 fect posts and fences by rubbing against them, and the parasites 

 escape from one sheep to another while the sheep are in close con- 

 tact in yards and sheds. These parasites may revive and become 

 infectious after a short exposure to severe cold weather, but are 

 soon destroyed by alternating changes of heat and cold. They 

 may live three to four weeks, at ordinary temperatures and under 

 ordinary conditions, around stables and sheds. Some authorities 

 say they do not live longer than two or three weeks apart from the 

 sheep's body, but it is certainly wise to extend this period to three 

 or four weeks for safety. 



FOOT SCAB. 



The disease caused by these parasites appears on the feet and 

 limbs. The diseased area extends very slowly, but may eventually 

 reach the body. This form of scab spreads very slowly from one 

 animal to another, and is therefore much less serious than body 

 scab. The first symptom is reddening of the skin followed by a 

 scaly appearance, and later by light-colored scabs. The sheep 

 having this disease are apt to be almost constantly stamping and 

 pawing. 



Local treatment. — Any of the sheep dips recommended for 

 body scab are effective for this form of the disease. A ten per 

 cent solution of the creolin is simple, safe and easilv applied. 



Any dip or ointment that will kill the parasites is sufficient 

 early in the disease, but it may be necessary in old cases to soften 

 the scabs by a little oil or a thorough scrubbing with brush and 

 hot soap suds. (See treatment.) 



HEAD SCAB. 



The mites which cause this type of the disease burrow tunnels 

 in the skin. The eggs are deposited in these tunnels and there 

 hatched. This type of the disease usually shows its first symp- 

 toms around the lips or nostrils, but may appear on almost any 



