804 
ILLUSTRATED STOCK DOCTOR. 
Selection Always Important. 
in animals usually having but one young at a time, the progeny pretty 
uniformly partake of the nature of both parents, and are bred with toler- 
ably uniform results. In animals producing a number of young at a time, 
the progeny will be found to vary very considerably in the same litter.' 
Thu3 the selection of those specimens that partake of uniform and char- 
acteristic excellence becomes of the first importance, since unwise\ 
selections will result in carrying the breeder farther and farther from the' 
excellent points to be perpetuated. Again, heredity, that is throwing 
back to an original type, or rather in the sense in which we use it, inher- 
iting certain fixables, as constitutional vigor, inclination to fat, etc., is 
shown far more clearly in animals having many young at a time, than 
those having only one young. The progeny will not only vary more in 
particular animals, but certain characteristics will- reappear by reversion 
after a greater number of generations, in animals having many young at 
a time, and to a greater degree than in those usually having but one. At 
least such is our experience. Hence, as we have stated, absolute necessity 
of the strictest care, is not only necessary in breeding, but iu the selection 
of animals for future breeding. 
In domestic animals it is a matter of common observation that the tem- 
per and other peculiarities of individuals arc determined by inheritance. 
Thus, virtually, quietness of disposition, or mildness, tractability or 
viciousness, courage or timidity, are constantly shown. Now from the 
general law that like produces like, and the well determined law that 
variation is a constant integer in all cross bred animals, and from our 
own observation that it is often intensified in animals having many young 
at a litter, the full force, as regards judgment in selection will be appa- 
rent ; and the fact that the country is not soon filled up with superior 
breeds of hogs is due mainly to the want of proper care in the selection 
of the breeding animals, and also from a lack of accurate knowledge and 
ability to nicely discriminate by the breeder, in regard to form, constitu- 
tional vigor, and excellent points in the young animals selected as breeders. 
Absolute accuracy in this respect is in fact possessed by but few individ- 
uals in a generation. There must first be a natural tact inherently 
possessed and digested and matured by years of study a,ud observation. 
Breeding Age of Swine. 
The sow is capable of breeding at about seven months of age, and th* 
boar is fit for service at the age of one year. As a rule, however, the 
sew should not be allowed to farrow under the age of fifteen months, and 
the boar is not fit for continued service until he is eighteen months old* 
