CONSANGUINITY 389 



to without any fear of the excellence being lost, and with the 

 expectation of an increased stimulus to vigour. 



It seems well established that some stable and important 

 breeds of cattle e.g., polled Angus have arisen under conditions 

 involving in the early stages extremely close inbreeding, and it 

 is well known in horse-breeding that very valuable results have 

 been reached by using the same stallion repeatedly on successive 

 generations. 



Thus, if we take the pedigree of the short-horn bull " Courtier/' 

 calved January 6th, 1896, owned by the Iowa Agricultural 

 College, we find from the tabulation given by Mr. R. W. Barclay 

 that " Champion of England " (17526) appears in the pedigree 

 over twenty-five times, and " on both sides of the house." We 

 find another famous bull, " Roan Gauntlet " (45276), functioning 

 over and over again in the lineage. Let us take, for instance, 

 the pedigree of the paternal grandfather of " Courtier " (see 



P- 39)- 



The whole subject has been recently illumined by East and Jones 

 in their fine work on Inbreeding and Outbreeding (1919). It is shown 

 that inbreeding of good stock, accompanied by judicious elimination 

 of " wasters," fixes desirable characters, and leads to a stable and 

 uniform herd. Yet it is sometimes associated with reduction of 

 vigour, resisting power, fecundity, and even size. This is not be- 

 cause of the consanguinity as such, but because the inbreeding 

 automatically brings into expression a number of undesirable 

 " recessive " characters, hidden in conditions of exogamy by their 

 " dominant " counterparts. But this exposure of undesirable 

 features may be utilised by the breeder for the useful purgation 

 of the herd. Needless to say, when the same undesirable features 

 occur on both sides~ of the house, inbreeding tends to diffuse and 

 exaggerate them. The value of exogamy or outbreeding is two- 

 fold. It brings about a greater variety of raw material on which 

 selective agencies can work. It also promotes " hybrid vigour " 

 by the pooling of diverse hereditary resources of good quality. 

 The crossing makes it more likely that a minus on one side may be 

 made good by a plus on the other, or that desirable dominants 

 may strengthen one another's hands. 



