The most precise account which I have met with is given by Stonehenge (15/12.
'The Dog' 1867 pages 179-184.) and is illustrated by photographs. Mr. Hanley
crossed a greyhound bitch with a bulldog; the offspring in each succeeding
generation being recrossed with first-rate greyhounds. As Stonehenge remarks,
it might naturally be supposed that it would take several crosses to get rid
of the heavy form of the bulldog; but Hysterics, the gr-gr-granddaughter of a
bulldog, showed no trace whatever of this breed in external form. She and all
of the same litter, however, were "remarkably deficient in stoutness, though
fast as well as clever." I believe clever refers to skill in turning.
Hysterics was put to a son of Bedlamite, "but the result of the fifth cross is
not as yet, I believe, more satisfactory than that of the fourth." On the
other hand, with sheep, Fleischmann (15/13. As quoted in the 'True Principles
of Breeding' by C.H. Macknight and Dr. H. Madden 1865 page 11.) shows how
persistent the effects of a single cross may be: he says "that the original
coarse sheep (of Germany) have 5500 fibres of wool on a square inch; grades of
the third or fourth Merino cross produced about 8000, the twentieth cross
27,000, the perfect pure Merino blood 40,000 to 48,000." So that common German
sheep crossed twenty times successively with Merino did not by any means
acquire wool as fine as that of the pure breed. But in all cases, the rate of
absorption will depend largely on the conditions of life being favourable to
any particular character; and we may suspect that there would be a constant
tendency to degeneration in the wool of Merinos under the climate of Germany,
unless prevented by careful selection; and thus perhaps the foregoing
remarkable case may be explained. The rate of absorption must also depend on
the amount of distinguishable difference between the two forms which are
crossed, and especially, as Gartner insists, on prepotency of transmission in
the one form over the other. We have seen in the last chapter that one of two
French breeds of sheep yielded up its character, when crossed with Merinos,
very much more slowly than the other; and the common German sheep referred to
by Fleischmann may be in this respect analogous. In all cases there will be