Chapter xi. 



peinoiples and^peaotioe op beeeding. 



Bebbdin-g, in its technical sense, as applied to thi 

 reproduction of domesticated animals under the directioi 

 of man, is the art of selecting such males and females t< 

 procreate together as are best adapted, ui conjunction, t 

 produce an improved and uniform offspring. The first am 

 most important fact to be kept in view, in pursuing the objec 

 of breeding, is that result of a fixed natural law which i 

 expressed in the phiase, " like produces like." The painte 

 oriole now flashing among the apple blossoms before m 

 window wears the same bright dyes that were worn by th 

 oriole ages ago. But the breeding maxim just quoted, i 

 understood to assert more than that species and varietie 

 continue to reproduce themselves: it implies that the specij 

 individual characteristics of parents are also transmitted t 

 progeny. This is the prevailing rule, but it has a broa 

 margin of exceptions and variations. Animals are oftentimc 

 more or less unlike their parents, yet inherit a very distinc 

 resemblance to remoter ancestors — sometimes to thos 

 several generations back. This is termed "breeding back. 

 And, moreover, where the' resemblance is to the immediat 

 progenitors, the mode of its transmission is not uniforn 

 Sometimes the progeny is strongly like one parent an 

 sometimes like the other; sometimes, and perhaps oftenest, : 

 bears a modified resemblance to both. 



The physiologicatl causes or laws which control th 

 hereditary transmission of physical forms and properties - 

 which determine the precise structure which the embryo sha 

 assume in the womb, and give to each animj^l a distinc 

 individuality which will accompany it through life an 

 distinguish it from every other animal of the same breed an 

 family — have not yet been, and probably never will b< 

 fully understood. Nor can we, by the closest study c 

 analogies or precedents, learn to anticipate their action wit 



