12 Michael Ruse
space I could quote numerous passages to this effect from highly com-
petent authorities. Youatt, who was probably better acquainted with
the works of agriculturists than almost any other individual, and who
was himself a very good judge of animals, speaks of the principle of se-
lection as “that which enables the agriculturist, not only to modify the
character of his flock, but to change it altogether. It is the magician’s
wand, by means of which he may summon into life whatever form and
mould he pleases.” Lord Somerville, speaking of what breeders have
done for sheep, says:
“It would seem as if they had chalked out upon a wall a form perfect
in itself, and then had given it existence.” [Darwin, 1859, 30–31]
You might think that this is all pretty obvious stuff. Darwin was leading the
reader into the main topics gently, by referring to his own route to discovery of
natural selection. But the discussion is intended to do more than this, for apart
from anything else, general opinion at the time was that the very thing you need
to do is to separate natural selection from artificial selection — the latter is very
limited and cannot support the former. Wallace, in his essay, argued explicitly
that there is no true analogy. Darwin to the contrary pushed the analogy, and
again and again through theOriginreturned to it. For instance, in his discussion
of embryology, he wanted to argue that the reason for the similarities of embryos
of very different adult forms is that selection does not work on the embryos, only
the adults. To make this point, he showed that animal breeders do not work on
the young, only the adults, and this shows.
Some authors who have written on Dogs, maintain that the greyhound
and bulldog, though appearing so different, are really varieties most
closely allied, and have probably descended from the same wild stock;
hence I was curious to see how far their puppies differed from each
other: I was told by breeders that they differed just as much as their
parents, and this, judging by the eye, seemed almost to be the case;
but on actually measuring the old dogs and their six-days old puppies,
I found that the puppies had not nearly acquired their full amount
of proportional difference. So, again, I was told that the foals of cart
and race- horses differed as much as the full-grown animals; and this
surprised me greatly, as I think it probable that the difference between
these two breeds has been wholly caused by selection under domestica-
tion; but having had careful measurements made of the dam and of a
three-days old colt of race and heavy cart-horses, I find that the colts
have by no means acquired their full amount of proportional difference.
(444–445)Adding: “Fanciers select their horses, dogs, and pigeons, for breeding, when they
are nearly grown up: they are indifferent whether the desired qualities and struc-
tures have been acquired earlier or later in life, if the full-grown animal possesses
them.” (446)