constitution, in-and-in breeding does not induce degeneracy; but he adds that
he "does not pride himself on breeding from the nearest affinities." In France
the Naz flock has been bred for sixty years without the introduction of a
single strange ram. (17/11. For the case of the Messrs. Brown see 'Gardener's
Chronicle' 1855 page 26. For the Foscote flock 'Gardener's Chronicle' 1860
page 416. For the Naz flock 'Bull. de la Soc. d'Acclimat.' 1860 page 477.)
Nevertheless, most great breeders of sheep have protested against close
interbreeding prolonged for too great a length of time. (17/12. Nathusius
'Rindvieh' s. 65; 'Youatt on Sheep' page 495.) The most celebrated of recent
breeders, Jonas Webb, kept five separate families to work on, thus "retaining
the requisite distance of relationship between the sexes" (17/13. 'Gardener's
Chronicle' 1861 page 631.); and what is probably of greater importance, the
separate flocks will have been exposed to somewhat different conditions.

Although by the aid of careful selection the near interbreeding of sheep may
be long continued without any manifest evil, yet it has often been the
practice with farmers to cross distinct breeds to obtain animals for the
butcher, which plainly shows that good of some kind is derived from this
practice. We have excellent evidence on this head from Mr. S. Druce (17/14.
'Journal R. Agricult. Soc.' volume 14 1853 page 212.), who gives in detail the
comparative numbers of four pure breeds and of a cross-breed which can be
supported on the same ground, and he gives their produce in fleece and
carcase. A high authority, Mr. Pusey, sums up the result in money value during
an equal length of time, namely (neglecting shillings), for Cotswolds 248
pounds, for Leicesters 223 pounds, for Southdowns 204 pounds, for Hampshire
Downs 264 pounds, and for the crossbred 293 pounds. A former celebrated
breeder, Lord Somerville, states that his half-breeds from Ryelands and
Spanish sheep were larger animals than either the pure Ryelands or pure
Spanish sheep. Mr. Spooner concludes his excellent Essay on Crossing by
asserting that there is a pecuniary advantage in judicious cross-breeding,