WOOL DESCRIBED AND CLASSIFIED 6l 



oiled, as it were, along their entire lengths. The color of 

 the fiber is usually a pure white, but in some instances it 

 is tinted with yellow shades, as when the yolk is present 

 in large quantities. When sheep are out of condition 

 the wool is dull and lusterless. 



In size the wool fibers vary greatly. These varia- 

 tions are in a marked degree the outcome of breeding, 

 but they are also influenced by climate and food. The 

 variations in length run all the way from less than 2 

 inches to 20 inches. The variations in the diameter of the 

 fiber are even greater. They run all the way from 

 i-3,oooth of an inch in the very finest of the merino types 

 to i-275th of an inch in the coarsest Algerian sheep. 



Each wool fiber is composed of two parts, known as 

 the stem or shaft and the root or bulb, out of which the 

 stem rises, and on which it is dependent for its sustenance. 

 The bulb or root imbedded in the derma is implanted in a 

 gland known as the hair follicle. It is simply an enlarge- 

 ment which fits somewhat socket-like into the fiber sack 

 which incases it. It rests upon a small bulb in the bot- 

 tom of the fiber sack. This small sack is at once the 

 source of and the support of the fiber. The hair follicle 

 is formed of the epidermis and the dermis of the sheep's 

 skin. It penetrates the body only for a short distance. 

 The blood vessels, in minute and numerous branches, are 

 distributed over the walls of the follicle. The nourish- 

 ment thus furnished is molded into the structure of the 

 fiber. Should a fiber be plucked out, a new one may be 

 produced to take its place. The hair or wool follicle is 

 to be carefully distinguished from the follicle which pro- 

 duces perspiration and that from which the yolk exudes. 



The shaft is that portion of the fiber which rises up 

 from the root bulb of the same, and continuing to grow 

 outward with other fibers, forms the fleece of the sheep. 

 All the elements of growth are furnished by the hair germ, 

 which rises into the hair bulb. It is not the function of 

 the yolk to furnish nutriment to the fiber. 



