The Origin of Species | Page 8

they may be traced, in
some cases, to distinct external influences; which are assuredly
competent to alter the character of the tegumentary covering, to change
colour, to increase or diminish the size of muscles, to modify
constitution, and, among plants, to give rise to the metamorphosis of
stamens into petals, and so forth. But however they may have arisen,
what especially interests us at present is, to remark that, once in
existence, varieties obey the fundamental law of reproduction that like
tends to produce like; and their offspring exemplify it by tending to
exhibit the same deviation from the parental stock as themselves.
Indeed, there seems to be, in many instances, a pre-potent influence
about a newly-arisen variety which gives it what one may call an unfair
advantage over the normal descendants from the same stock. This is
strikingly exemplified by the case of Gratio Kelleia, who married a
woman with the ordinary pentadactyle extremities, and had by her four
children, Salvator, George, Andre, and Marie. Of these children
Salvator, the eldest boy, had six fingers and six toes, like his father; the
second and third, also boys, had five fingers and five toes, like their
mother, though the hands and feet of George were slightly deformed.
The last, a girl, had five fingers and five toes, but the thumbs were
slightly deformed. The variety thus reproduced itself purely in the
eldest, while the normal type reproduced itself purely in the third, and
almost purely in the second and last: so that it would seem, at first, as if
the normal type were more powerful than the variety. But all these
children grew up and intermarried with normal wives and husband, and
then, note what took place: Salvator had four children, three of whom
exhibited the hexadactyle members of their grandfather and father,
while the youngest had the pentadactyle limbs of the mother and
grandmother; so that here, notwithstanding a double pentadactyle
dilution of the blood, the hexadactyle variety had the best of it. The
same pre-potency of the variety was still more markedly exemplified in
the progeny of two of the other children, Marie and George. Marie
(whose thumbs only were deformed) gave birth to a boy with six toes,
and three other normally formed children; but George, who was not
quite so pure a pentadactyle, begot, first, two girls, each of whom had

six fingers and toes; then a girl with six fingers on each hand and six
toes on the right foot, but only five toes on the left; and lastly, a boy
with only five fingers and toes. In these instances, therefore, the variety,
as it were, leaped over one generation to reproduce itself in full force in
the next. Finally, the purely pentadactyle Andre was the father of many
children, not one of whom departed from the normal parental type.
If a variation which approaches the nature of a monstrosity can strive
thus forcibly to reproduce itself, it is not wonderful that less aberrant
modifications should tend to be preserved even more strongly; and the
history of the Ancon sheep is, in this respect, particularly instructive.
With the "'cuteness" characteristic of their nation, the neighbours of the
Massachusetts farmer imagined it would be an excellent thing if all his
sheep were imbued with the stay-at-home tendencies enforced by
Nature upon the newly-arrived ram; and they advised Wright to kill the
old patriarch of his fold, and install the Ancon ram in his place. The
result justified their sagacious anticipations, and coincided very nearly
with what occurred to the progeny of Gratio Kelleia. The young lambs
were almost always either pure Ancons, or pure ordinary sheep.* But
when sufficient Ancon sheep were obtained to interbreed with one
another, it was found that the offspring was always pure Ancon.
Colonel Humphreys, in fact, states that he was acquainted with only
"one questionable case of a contrary nature." Here, then, is a
remarkable and well-established instance, not only of a very distinct
race being established 'per saltum', but of that race breeding "true" at
once, and showing no mixed forms, even when crossed with another
breed.
[footnote] *Colonel Humphreys' statements are exceedingly explicit on
this point:--"When an Ancon ewe is impregnated by a common ram,
the increase resembles wholly either the ewe or the ram. The increase
of the common ewe impregnated by an Ancon ram follows entirely the
one or the other, without blending any of the distinguishing and
essential peculiarities of both. Frequent instances have happened where
common ewes have had twins by Ancon rams, when one exhibited the
complete marks and features of the ewe, the other of the ram. The
contrast has been rendered singularly striking, when one short-legged

and one long-legged lamb, produced at a birth, have been seen sucking
the dam at the same