f a long chase in this attenuated atmosphere, and before they
could come up with their prey they lay down gasping for breath; but these
same animals have produced whelps, which have grown up, and are not in the
least degree incommoded by the want of density in the air, but run down the
hares with as much ease as do the fleetest of their race in this
country."[80]

We have here no action of "Natural Selection;" it was not that certain
puppies happened accidentally to be capable of enduring more rarefied air,
and so survived, but the offspring were directly modified by the action of
surrounding conditions. Neither was the change elaborated by minute
modifications in many successive generations, but appeared at once in the
second.

With regard once more to sudden alterations of form, Nathusius is said to
state positively as to pigs,[81] that the result of common experience and
of his experiments was that rich and abundant food, given during youth,
tends by some direct action to make the head broader and shorter. Curious
jaw appendages often characterize Normandy pigs, according to M. Eudes
Deslongchamps. Richardson figures these appendages on the old "Irish
greyhound pig," and they are said by Nathusius to appear occasionally in
all the long-eared races. Mr. Darwin observes,[82] "As no wild pigs are
known to have analogous appendages, we have at present no reason to {100}
suppose that their appearance is due to reversion; and if this be so, we
are forced to admit that somewhat complex, though apparently useless
structures may be suddenly developed without the aid of selection." Again,
"Climate directly affects the thickness of the skin and hair" of
cattle.[83] In the English climate an individual Porto Santo rabbit[84]
recovered the proper colour of its fur in rather less than four years. The
effect of the climate of India on the turkey is considerable. Mr. Blyth[85]
describes it as being much degenerated in size, "utterly incapable of
rising on the wing," of a black colour, and "with long pendulous appendages
over the beak enormously developed." Mr. Darwin again tells us that there
has suddenly appeared in a bed of common broccoli a peculiar variety,
faithfully transmitting its newly acquired and remarkable characters;[86]
also that there have been a rapid transformation and transplantation of
American varieties of maize with a European variety;[87] that certainly
"the Ancon and Manchamp breeds of sheep," and that (all