212 Pigs: their Breeding and Management. 
always be borne in mind between the crossing of different breeds, 
and the crossing of different strains of the same breed. In the 
former case the result is necessarily a cross-bred animal ; but 
in the latter the purity is naturally retained, with the manifest 
advantage of an introduction of new blood. Whilst the fact has 
been recognised thatour improved breeds have all been established 
by the crossing of distinct races, the character of each of 
late years has been sustained and improved by selection and 
crossing of animals from the different strains of the same breed 
thus established. 
The greatest claim that any herd or flock has to purity of breed 
may be computed by the length of time which has elapsed since its 
crossing with any other breed. The proof of recent use of any 
other breed in a herd will generally be seen in the progeny ; if a 
cross has been recent, the characteristics in respect of colour, 
shape, and size of the progenitor will often obtrude. It is 
remarkable to note that, even after the lapse of twenty years, 
distinct features of a former cross will appear. This shows 
how much care and judgment are necessary in the selection 
of animals by breeders who care to maintain uniformity of 
character. 
Some fourteen years ago, I was induced to buy a first-prize 
boar exhibited at one of our principal shows. He was a very 
perfectly shaped animal, and was declared to be out of a sow 
of my own breeding ; but about his pedigree I was deceived. 
The result of his introduction into my herd was most disastrous, 
and not until the blood had been completely eliminated, did 
I get clear of his evil influence. In cases where, for stock 
purposes, breeding in-and-in is resorted to, the most vigorous of 
the litters of both sexes should be selected. Especial care 
should, however, be paid to the selection of the male. The 
late Mr. Fisher Hobbs was in his earlier career a most successful 
breeder of pigs. He used to boast tliat for twenty-five years he 
had never gone away from his own herd. Under such circum- 
stances he had of necessity very often to breed from animals very 
closely related. His practice was to select the strongest of the 
progeny on both sides : by this means he obtained a few animals 
of great merit, but after pursuing the practice for some years, a 
large proportion of the litters were small, ill-shaped, and many 
of them deformed. If fecundity, freedom from disease, and 
strength of constitution are to be maintained, frequent change 
of blood is a necessity ; for pigs, according to my experience, 
degenerate more rapidly from in-and-in breeding than any other 
animal. Where the maintenance of uniformity of character is a 
point of importance, as with exhibitors, change of blood should 
be introduced on the female side, inasmuch as the male has so 
