98 QUEENSLAND AGRICULTURAL JOURNAL. [1 Fes., 1898. 
will suppose the breeder now resolves to fix it by using only bulls of this grade. 
It will be understood that in that case the herd will never approach nearer 
purity of Hereford blood than seven-eighths, even although the breed may be 
continued up to 100 generations. But what the breeder has now to contend 
with is Atavism, or what horsebreeders term “ harking back” to some distant 
ancestors. This tendency is always strong in even pure pedigreed animals, 
but doubly or trebly so in mixed breeds. Of the successive progenies, it 
will probably be found that one-third or even one-half will show a tendency 
to reversion to the Shorthorn, the remainder to Hereford ancestry, for the 
reason that the prepotency has been weakened on both sire and dam. ‘The 
breeder cannot attain an undeviating result, even with the closest culling 
out, until after the lapse of many years. While this difficulty is met with 
in all efforts at establishing a new variety of cattle, it will be found to be 
greatly increased in attempts at establishing a permanent variety of sheep 
founded on a cross between the merino and any coarse-woolled breed, for 
the reason that the breeder has the question of wool to take into con- 
sideration in addition to carcass. For that reason, there is not the same 
uniformity of success in a first cross between the merino and any given 
coarse-woolled breed as there is with a first cross in cattle ; and even when 
the cross is between two types of the same breed, such as that of the 
American and Australian merino, cited above, the same law prevails, although 
in a less degree. The prepotency may, and in all probability will, be unfairly 
represented, and for several generations the breeder will have to contend with 
the tendency to reversion, which will seriously disturb the establishment of a 
fixed type, and necessitate the most close and careful culling. 
