WOOL DESCRIBED AND CLASSII'IED 63 



greatest number of imbrications to the square inch require 

 the greatest amount of yolk. Such is the wool of the 

 Merino, with its high felting properties. Yolk is liquid 

 when it exudes from the yolk glands, and in some breeds 

 it remains so ; but in others it turns into gummy or waxy 

 orange-yellow scales, which adhere to the wool. Even 

 when it thus accumulates it does not materially weaken 

 the strength of the fibers. 



The chief of the influences that afiFect yolk in wool 

 are food, protection and breeding. The relation between 

 liberal feeding and the plentiful production of yolk is of 

 the closest nature. Food that promotes thrift also tends 

 to increase the amount of yolk in the wool. The rela- 

 tion between food and yolk is so intimate that the differ- 

 ence in the amount of the same and the difference in the 

 strength of the wool resulting will be apparent on differ- 

 ent soils separated only by a river bed. Protection, as by 

 housing when rain storms prevail and by blanketing un- 

 der certain conditions, not only tends to keep the yolk in 

 condition, but it also tends to increase in its accumulation. 

 The quantity of yolk in wool may be increased or de- 

 creased through transmission in breeding. Such trans- 

 mission may be looked for when breeding pure breds or 

 grades. 



The amount of yolk that is desirable and the condi- 

 tions in which it is found are by no means unimportant. 

 With reference to the former, however, there is not en- 

 tire agreement. Yolk is seldom present in excess as long 

 as it remains in the liquefied form, and colorless or nearly 

 so, in the unshorn fleece. It is usually in excess when it 

 forms dry or pasty masses in the wool, nor is it in a de- 

 sirable condition when exposure to rain washes it down 

 so as to form a pasty, gluey mass in the fleece. Yolk is 

 deficient in wool when the latter lacks softness and 

 pliancy to the touch and when it lacks brilliancy of luster 

 when the fleece is opened out. 



