44 



'A LITTLE JOURNEY 



two original units from which is bred the strain. The first year, for instance, 

 the original pair produce group 2, whose blood is half-and-half of each. The 

 second year the original female, or one of them, is bred to a cockerel from 

 group 2, and the original male to a pullet from group 2. Thus are produced 

 groups 3 and 4, each of which possesses three-fourths of the blood of the unit 

 on its own side of the diagram. Here begins the real work of the breeder, 

 since these mates now taken from group 2 must be most carefully selected 

 to type, according to that 'course of selection' which we have already discussed. 

 From the very first all depends on this, and, of course, the two original units 

 have been chosen with equal care, so far as money and opportunity allowed. 

 The third year a cockerel from group 3 is mated with the original hen to pro- 

 duce group 5, and pullets from group 4 to the original male to produce group 

 7, all of which possesses seven-eighths of the blood of their own side, and are 

 to be rigorously selected true to type as before. 



