378 EXPERIMENTAL STUDY OF INHERITANCE 



introduced. The first bad effect of inbreeding is some loss 

 of size in successive generations. Afterwards come impaired 

 constitution and fertility." If the breeder introduces a strongly 

 inbred sire of a different line there is conflict between the two 

 powerful strains. " The type is apt to be destroyed and the 

 progeny sports in many directions. Probably the safest course 

 is to use a sire of rather mixed blood, and then the chances are 

 that the concentrated female blood will continue to rule the type 

 of the progeny, and a substantial gain in vigour and fertility 

 will be secured." 



The following case, due to Mr. Marr, is of some interest. Two 

 Clydesdale staUions, full brothers, were of very different type. 

 One was of the pure Clydesdale type, and was very prepotent in 

 breeding true to that type. The other was nearly of the Clydesdale 

 type, but with a trace of the Shire in his appearance, and he was 

 a very prepotent getter of stock more hke the Shire than himself. 

 The sire of these stallions was a very pure Clydesdale, the dam 

 had a small admixture of Shire blood. There was here, perhaps, 

 the beginning of a sifting out of the Shire character. 



As is well known, the Shorthorn, the Hereford, and the Aber- 

 deen Angus are the three leading breeds of beef cattle, each 

 very prepotent according to its kind. Mr. Marr relates a 

 remarkable instance of the result of crossing these three breeds, 

 which came under his personal observation. A cross bull, whose 

 sire was a pure Hereford bull and whose dam was a Shorthorn- 

 cross cow, was mated with a pure black polled Aberdeen Angus 

 cow. The colour of the Shorthorn- cross cow is a little 

 uncertain, but it is believed to have been red with a little white. 

 The colour of the cross bull was red with white face and hind 

 legs. In any case there was an interesting mixture of breeds, 

 and the produce was a beautiful creamy white heifer, with 

 black muzzle and black hair on the inside and tips of the ears. 

 She had a very stylish head and horns, and bore a striking 

 resemblance to ChilHngham white cattle. Other nine calves 



