2QS [Assembly 



to could be deemed examples of in-and-in-breeding, except that 

 of brother and sister, as they are the only ones in which the blood 

 is the same on both sides. With half-bloods, derived from an 

 union of any one animal with animals of alien blood, it is evi- 

 dent there is considerable diversity, owing to the variation of 

 blood in one of the parent stock ; as in the case of a cross of the 

 Devon bull, before mentioned, the half-bloods are only the same 

 in blood to the amount of one-half. This difference exists also, 

 but in a less degree, in most cases where offspring are bred to 

 either of iiie parents. If, for instance, a male and female of dif- 

 ferent families are united, the offspring inherits half the blood of 

 each parent. The produce of this offspring with either of the 

 parents, would be three-fourths of one of the first pair, and one- 

 fourth of the other. This produce, bred to the same animal 

 again, would give the third generation seven-eighths of one of 

 the original stocks and one eighth of the other. The terms breed- 

 ing-in^ and close breedings have been given to this and similar 

 Xiourses. It is obvious, however, that whatever are the conse- 

 quences of in-and-in breeding, thuse of breeding-in must approxi- 

 mate to them in proportion to the closeness to which the practice 

 is carried, and in proportion as the blood of the animals becomes 

 similar. 



With these remarks in reference to the meaning of the term 

 in-and in, let us return to our text, the first clause of which de- 

 clares that that system of breeding " is not desirable/' The ex- 

 pression indicates that its author regarded in-and-in bretding as 

 fraught with certain tendencies of an injurious nature, an idea by 

 no means uncommon. But what are ti^e injurious results attri- 

 buted to in-and-in breeding? Perhaps the common hypothesis in 

 regard to this subject cannot be better expressed than by the fol- 

 lowing language from, the essay of Sebright, before referred to: 



•' I have tried many experiments by breeding in-and-in, upon 

 dogs, fowls and pigeons ; the dogs became from strong spaniels, 

 weak and diminutive lap-dogs ; the fowls became long in the legs, 

 small in the body, and bad breeders. Indeed I have no doubt 

 but that by this practice being continued, animals would in the 

 course of time degenerate to such a degree as to be incapable of 

 breeding at all." 



