37 



breeding with mothers, or of brothers with sisters, is small 

 compared to the regular and extensive majority of sires breed- 

 ing each season with their female progeny. 



In pedigree No. 2 you will see the effect of four genera- 

 tions breeding back to the mother's race. But to be a toler- 

 ably perfect experiment you will remark that in this case it is 

 necessary that the 50 ewes or 50 B shall be whole sisters. 

 In breeding back to the father's line, from the powder the male 

 possesses of impregnating numbers, the relationship of his 

 ewes, one to the other, does not signify to the same extent. 

 Indeed, unless quite certain that they are of the highest 

 strain, it is better when starting a station that they should 

 not be whole sisters. For if not of the highest known strain 

 the breeder would lose the superior chance offered by putting 

 60 ewes of similar but not so closely allied family, the 

 chance of some atavism in some of them being awakened 

 and called out which should hit in with the male and produce 

 some exceptional animals. 



To return to pedigree No. 2. If the ewes are not whole 

 sisters the experiment no longer carries out its intention, 

 as you will see by reference to pedigree No. 5, where I letter 

 the different ewes B C D E F. Turning to pedigree No. 4, if 

 B has a male lamb the experiment is only so far perfect that 

 I can breed him with his mother, and there will be 24 other 

 ram lambs to breed back with their mothers. The 25 ewes 

 that produce ewe lambs are out of the experiment, and those 

 ewe lambs go to strengthen pedigree No. 1 and its effects. 



I must, you perceive, breed each ewe that has a ram lamb 

 with that son, or I do not breed back to her blood. For, if 

 I take any one ram lamb, say AB, and breed it next genera- 

 tion with all the ewes, they, not being sisters, would merely 

 receive and transmit B's influence, without in the least 

 effecting our purpose. AB with his mother would get, it is 

 true, AB2 or B^ A, but with the 24 other ewes, who are 

 C D E F G, the result would only be ABC, ABD, ABE, 

 ABF, ABa. 



If AB begets from his mother a ram lamb or AB^ the next 

 generation would be AB^ , AB^ D, AB^ E, etc. 



But this is not pure line breeding back to the mother, 

 except with one individual, and at any moment that too is 

 liable to stop, by B's progeny being female. 



Again, if all the ewes are sisters, and you each generation 

 breed AB and AB^ with the original mothers, it is only 

 an approximation, and AB breeds back only with one mother 

 and 49 aunts. 



I have gone into this to prove that without extraordinary 

 trouble pure line breeding back to the maternal line is 



