190 BRITISH SHEEP AND SHEPHERDING. 



black sheep as a basis, it would breed true black with black, 

 and although when mated with white, would disappear in the 

 first generation, it would reappear as black in the second genera- 

 tion, as the following table indicates. 



BLACK CROSSED INTO WHITE KZCESSIVI BLACK cfiosso wro 



I 



e 



BLACK 



O - WH/TE W 



Q - BLACK (M. 



- iv ///re M* 



So that from one black sheep only it is quite possible to develop 

 a black flock by careful in-breeding with white. 



The problem of the pure black sheep, however, is a very simple 

 problem in comparison with the problem of grey or dark hairs in 

 white wool. Certain breeds of sheep have a most marked tendency 

 to produce these grey hairs, and as such wools cannot be used for 

 pure whites, their value is markedly depreciated. The writer has 

 seen staples of wool white for a certain length and then black. 

 This seems to suggest that the pigmentation of the naturally- 

 coloured wools is independent of their growth. If so, it is con- 

 ceivable that means might be found of arresting the production of 

 pigment, with a concomitant increase in the value of the wool as 

 " pure white." 



Reference has already been made to the effect of food on the 

 wool. It is popularly supposed that if the Lincoln sheep be taken 

 from South Lincolnshire into Norfolk a distance of a few miles 

 it at once loses its lustre and markedly depreciates in value. Environ- 

 ment undoubtedly does affect wool to a considerable extent, and 



