260 THE DOMESTIC SHEEP. 



all concerning this easily susceptible animal. Any kind of 

 steady, unchanging conditions it will withstand, but changes 

 are as trying to a sheep as to a person who is wrapped in 

 a heavy overcoat every day in the year. 



The most common disease in wool is that commonly 

 called break. It cannot be perceived by the naked eye, but 

 is very easily discovered by stretching a small lock of wool. 

 Then any weak spot in it breaks, and this if examined under 

 a microscope shows this kind of defect (fig. 32) in the fiber. 

 This sample was taken from the fleece of a sheep which had 

 died through exposure and starvation, on the range, and the 

 severity .of its sufferings may be understood by comparing 

 a fiber from a sheep well cared for through the same Winter 



FIG. 31. FIG. 32. 



Healthy liber of wool. Break in wool A diseased fiber 



in the same locality with it (fig. 31). These samples were 

 taken from the common native sheep which have a small 

 infusion of Southdown blood in them, somewhat far back, 

 but sti'll show it in their occasional smutty faces and legs. 



This defect is equivalent to a diary, or nearly so, of the 

 sheep's condition. When the first failing occurs the weak 

 spot is of course at the skin, but as the fleece grows this 

 weak spot is carried up, and although the fault may not hap- 

 pen again this evidence of it remains in the wool. If it is 

 repeated, the same failing is marked on the record, and so on, 

 until the sheep is shorn, when the fleece is worthless if it is 

 badly defective, and lessened in value proportionately with 

 the amount of defect in it. It is really the most common 

 defect in wool. 



Another disease is that commonly known as stripy wool. 

 This affects the fleece in the most valuable part of it, 



