138 iLVTIXG AND SELECTION. 



but where tliis lias been tried on the middle-wooled breeds re- 

 sults were moderate, not effecting any permanent improvement, 

 and often, as in the case of the Southdown breed, were far from 

 successful or virtually failures. So it must be borne in mind 

 that crossing in the main is experimental, at times succeeding 

 beyond the breeder's most sanguine expectations, at others fail- 

 ing entirely for no visible reason. Where judgment 

 assists in the process is in selecting the successful results, per- 

 petuating them and rejecting the failures. In this manner after 

 a few generations a breed of sheep is sometimes produced which, 

 as in the case of the improved Oxford Downs, Shropshires, and 

 some others we could mention, are desirable to perpetuate with- 

 out the further admixture of foreign blood. 



Another subject of great importance to breeders is "in-and- 

 in bi-eeding". This process as applied to the human family 

 would be found highly objectionable, for the reason that among 

 people marriages are contracted with little if any regard to the 

 health of the individuals concerned, and certainly without an 

 extensive knowledge of each other's family history. For in- 

 stance, we tind a healthy man marrying a consumptive feiaiale 

 to perpetuate the fault? of her constitution to his offspring, or a 

 healthy young woman marrying a syphilitic man to hand down 

 a curse to four generations of their descendants. Xow should 

 the offspring of these ill-sorted couples inter-marry the predis- 

 position to the disease already inherited would be increased two- 

 fold. A scrofulous brother and sister, from sexual intercourse, 

 could only beget diseased progeny; but supposing that a family 

 had been bred by careful selection, if for generations the ancest- 

 ors on the male side had been always healthy and well formed, 

 and the saine could be said of the ancestors on the female side, 

 what danger could be apprehended from a cross in, as breeders 

 term it, viz: the intercourse of brother and sister, or son with 

 parent, where there were no defects to be transmitted, none 



