262 Agricultural Chemistry. 



to 50 per cent in damp weather. Raw wool consists of (1) yolk 

 or wool-grease; (2) suint; and (3) the pure wool hair. The first 

 two may constitute from 30 to 80 per cent of the weight of the 

 unwashed wool. The yolk is made up of fatty or wax-like bodies, 

 of complex composition and insoluble in water. In a washed 

 fleece the yolk may vary from more than 30 per cent to less than 

 8 per cent. Short fine wool contains the largest proportion of 

 yolk. The suint is an excretion of the perspiration glands of the 

 skin and consists of potassium salts of fatty acids, together with 

 phosphates, sulphates and chlorides. It is soluble in water and 

 consequently, removed by washing. It may amount to 50 per cent 

 of the weight of unwashed wool, but with a sheep exposed to the 

 weather, the quantity may be 15 per cent or less. 



The pure wool fiber is, for the most part, a protein and contains 

 about 16 per cent of nitrogen and 3.6 per cent of sulphur. A 

 large proportion of the nitrogen of a sheep ? s body is found in the 

 wool. The fact that wool production is at the expense of proteins 

 must indicate that a somewhat narrower ration is demanded than 

 for mere fattening. Wolff fed two sheep on rations consisting of 

 hay and bean meal, which supplied proteins liberally and main- 

 tained the weights of the animals. Two others received at the 

 same time, oat straw and roots, and lost slightly in weight. The 

 yield of pure wool fiber in the first case was 12.9 pounds and in 

 the second 10.0 pounds. It appears from this that under poor 

 treatment the yield of wool will be seriously diminished. Ex- 

 periments further show that on liberal fattening rations, the pro- 

 duction of wool is no greater than when the ration is just sufficient 

 to maintain the animal. However, from the experiments of others. 

 it appears that on somewhat scanty rations, the body may lose 

 weight without the production of wool being seriously affected. 

 All this emphasizes the fact that for the health and vigor of the 

 animal producing this nitrogenous coat, the protein supply must 

 not fall too low. 



The high favor in which such root crops as turnips and ruta- 

 bagas are held by sheep feeders may find its explanation in their 



