Wool. fi7 



involved that it matters little whether the cross is made 

 through the male or through the female. It is obvious, 

 however, that the greater number of females in the normal 

 environment will usually be the basis of any cross, the male 

 sheep being an introduction from another district or country. 

 It is obviously the duty of the sheep breeder to look out for 

 favourable variations and to work on such for the improvement 

 of his breed ; but the very question of variation is so mixed 

 up with cross breeding that it is equally important to be 

 fully conversant with the most recent Mendelian investiga- 

 tions, as such are throwing much light on the principles of 

 breeding. It may also be equally true that empirical sheep 

 breeding may throw much light on the principles of heredity 

 as interpreted by Mendelism. 



If a sheep were a unit factor and not a conglomeration 

 of innumerable factors sheep breeding would be readily dealt 

 with on Mendelian lines. But such is not the case. So far 

 as can be judged from the experiments carried out by 

 Professor Wood on the Cambiidge Univert-ity Farm the case 

 of crossing sheep appears to be somewhat analogous to that of 

 the blue andalusian fowl.' The first shows an intermediate 

 form in some sense between the two parents, and the second 

 cross shows reversions to the parental form, and further pro- 

 duction of first cross varieties which will probably show 

 certain differences. There is a saying in Australia — two 

 generations to find a breed, and seventeen to fix it. Working on 

 the lines already initiated by Professors Bateson, Wood, 

 Punnett and others, it does seem probable that at least the 

 seventeen generations may be considerably limited. But there 

 is much work yet to be done in this direction and assistance 

 is much needed by those who hold large flocks. The problem 

 of how to eliminate the black sheep from the Wensleydale 

 breed for example, is one full of intert st. It is probably 

 recessive and will breed true with itself : but to eradicate 

 it from the breed is a more difficult problem. Incidentally 

 it may be noted that to the manufacturer the eradication of 

 i-ingle black hairs in otherwise white fleeces is of even greater 

 importance. 



Although th" influence of environment has been very fully 

 discussed, and at least partially investigated, still so far as 

 sheep are concerned there is practically little certainty. For 

 example, although it is generally considered impossible to 

 grow Merino wool in this country, there are no reliable 



^ See Darbishire's Breeders and the Mendelian Disrorery. This suggestion 

 has been brought into question by the research work of Mr. J. Bailey, of 

 Cambridge University, recently carried out at the P.radford Technical College ; 

 and also by certain experiments in the crossing of cottons. 



F 2 



