mall beaks that they can
hardly eat and will not rear their own young; he has made families of
sheep with so strong a tendency to early maturity and to fatten, that in
certain pastures they cannot live from their extreme liability to
inflammation; he has made (_i.e._ selected) sub-varieties of plants with
a tendency to such early growth that they are frequently killed by the
spring frosts; he has made a breed of cows having calves with such large
hinder quarters that they are born with great difficulty, often to the
death of their mothers{208}; the breeders were compelled to remedy this
by the selection of a breeding stock with smaller hinder quarters; in
such a case, however, it is possible by long patience and great loss, a
remedy might have been found in selecting cows capable of giving birth
to calves with large hinder quarters, for in human kind there <are> no
doubt hereditary bad and good confinements. Besides the limits already
specified, there can be little doubt that the variation of different
parts of the frame are connected together by many laws{209}: thus the
two sides of the body, in health and disease, seem almost always to vary
together: it has been asserted by breeders that if the head is much
elongated, the bones of the extremities will likewise be so; in
seedling-apples large leaves and fruit generally go together, and serve
the horticulturalist as some guide in his selection; we can here see the
reason, as the fruit is only a metamorphosed leaf. In animals the teeth
and hair seem connected, for the hairless Chinese dog is almost
toothless. Breeders believe that one part of the frame or function being
increased causes other parts to decrease: they dislike great horns and
great bones as so much flesh lost; in hornless breeds of cattle certain
bones of the head become more developed: it is said that fat
accumulating in one part checks its accumulation in another, and
likewise checks the action of the udder. The whole organization is so
connected that it is probable there are many conditions determining the
variation of each part, and causing other parts to vary with it; and man
in making new races must be limited and ruled by all such laws.

{208} _Var. under Dom._, Ed. ii. vol. II. p. 211.

{209} This discussion corresponds to the _Origin_, Ed. i. pp. 11
and 143, vi. pp. 13 and 177.

_In what consists Domestication._

In this chapter we have treated of variation under domestication,