THE DISEASES OF SHEEP 305 



to do so to protect others. The Federal authorities could 

 not go on the ranges and quarantine the sheep, but 

 as soon as offered for interstate shipment it could 

 quarantine and thus force the owner to take care of 

 them. 



The states were generally quick to co-operate with the 

 Government in this matter, and in the most of them they 

 worked hand in hand, with very satisfactory results. 

 Naturally where a state has once been freed from this 

 disease a moderate amount of supervision and watch- 

 fulness on the part of the local authorities will pre- 

 vent any further spread of the trouble. 



Scab is one of the oldest of animal diseases. Moses 

 in his voluminous instructions to his followers, speak- 

 ing of sheep offered as sacrifices to the Lord, says in 

 Leviticus 22 :22 : 



"Blind or broken, or maimed, or having 

 a wen, or scurvy or scabbed, ye shall not 

 make an offering." 



Scab exists almost everywhere where sheep are raised. 

 In Europe, Asia and Africa it is common. Australia 

 fought it with success and very little of it is to be 

 found among the millions of sheep there. The cause is 

 a species of mite known as Psoroptes communis. Pso- 

 roptes is a Greek word meaning "mites that hide under 

 the skin." Horses and cattle also have scabies, but 

 the mites are different, and the disease cannot be car- 

 ried from a sheep to a cow, or vice versa. It can, how- 

 ever, be contracted by man. Sheep have been known to 

 contract the disease after being bedded down on a 

 bed-ground which sheep had not used for more than a 

 year. As the disease is carried entirely by the mites 

 they must have lived in the ground for that long at least. 



