GENERAL INTRODUCTION. Ixv 



coloratiou test^ one of the most, if not the most highly 

 specialised breed of dogs in existence. 



The conclusion arrived at from my experiments is^ that 

 I would not like to trust to the prepotency in the male 

 making up for deficiencies in the female. From the two 

 Clydesdale hybrids — full sisters — differing in so marked 

 a manner, the one, as already explained, taking after the 

 mare, the other after the zebra, and from members of the 

 same family varying greatly, both mentally and physically, 

 it seems to me breeders need not build much on the 

 supposed prepotency of the male beyond what he has 

 acquired through inbreeding, or by being a '^ sport." 

 In all the offspring of my Arab Benazrek there is a 

 characteristic blaze. This might be to some sufficient 

 proof of prepotency. But a blaze may be of the nature 

 of a " sport," and if this is not the right explanation his 

 breeding has to be taken into consideration. He is not 

 only well-bred, he is highly bred ; whereas the dams of 

 his offspring, with the possible exception of Mulatto, are 

 of mixed origin, or, as we say, cross-bred. That the 

 internal organs are not specially derived from the female 

 I have very strong evidence. Elsewhere I shall show 

 that a hybrid filly, out of an inbred mare and a zebra 

 horse, is zebra-like in some of her most distinctive in- 

 ternal organs. This is not, I think, because of the 

 influence of the wild sire, but because these organs in 

 the zebra are simpler than in the horse. It is doubtless 

 easier transmitting simple ancient structures than highly 

 specialised recently acquired structures. 



From what has been already written it will be evident 

 that I generally agree with the third and fourth articles 

 in Mr. Howard's creed. Other things being equal, 

 '' the parent of the purest descent will have the greatest 

 influence." But who will undertake to say what purity 

 of descent means ? It is not enough to know whether 

 any given animal has been bred on an equal or an unequal 

 factor system, whether one ancestor predominates or 

 several are about equally represented. Allowance has 

 to be made on the one hand for variation, on the other 



