Reversion to an Antecedent Form. 93 
dog with man would lead to great attention being paid to 
the favourite animal, and the least observant people would 
hardly fail to perceive the result of crossing, and to endeavour 
to direct spontaneous variation by selection. Since this has 
been going on in different parts of the world, among various 
races of men, from a remote period, each race taking as its 
starting point the original indigenous wild stock or stocks 
of the country; and, since these races have in many instances 
come into contact, and crosses have taken place between their 
dogs, there has been a repeated mixture of blood to lay 
the foundation for the strongly marked variations of the 
present day. Then, also, in this century, or, more exactly, 
within the past fifty years, we have applied systematic methods 
to the breeding of all our domestic animals, and variation 
has progressed with rapid stridés, especially in the case of 
the dog. Every breeder knows how comparatively unstable 
the more extreme of these variations are at present, and 
how strong a tendency the young often exhibit to return to 
one or other of the ancestral forms. He carefully weeds out 
and destroys the puppies that do not come true to his ideal, 
lest the reputation of his kennel should suffer by the appearance 
of anything true to Nature and false to art. He finds it 
impossible to suppress this evidence of the repeated mixture 
the blood of the dog has undergone, Reversion is thus con- 
stantly proclaiming the genealogy of the dog; though in 
the main we are on the way to the creation of permanent 
forms, if indeed we have not already attaied permanency 
in certain directions. The breeder of bulldogs or greyhounds, 
for example, would probably love me little for doubting whether 
he has yet attained complete fixity of species; but if all the 
productions from the most carefully selected parents were 
allowed to grow up, a considerable proportion of them would 
be very far indeed from his standard of “ breed.” 
I am inclined to regard the occasional subsequent appearance 
of young similar to the stock proper to a first alliance as merely 
the recurrence of one of those numerous varieties, of which 
