erfect teeth; long-haired and coarse-haired
animals are apt to have, as is asserted, long or many horns; pigeons
with feathered feet have skin between their outer toes; pigeons with
short beaks have small feet, and those with long beaks large feet. Hence
if man goes on selecting, and thus augmenting, any peculiarity, he will
almost certainly modify unintentionally other parts of the structure,
owing to the mysterious laws of correlation.

The results of the various, unknown, or but dimly understood laws of
variation are infinitely complex and diversified. It is well worth while
carefully to study the several treatises on some of our old cultivated
plants, as on the hyacinth, potato, even the dahlia, etc.; and it
is really surprising to note the endless points of structure and
constitution in which the varieties and sub-varieties differ slightly
from each other. The whole organisation seems to have become plastic,
and departs in a slight degree from that of the parental type.

Any variation which is not inherited is unimportant for us. But the
number and diversity of inheritable deviations of structure, both
those of slight and those of considerable physiological importance,
are endless. Dr. Prosper Lucas' treatise, in two large volumes, is the
fullest and the best on this subject. No breeder doubts how strong is
the tendency to inheritance; that like produces like is his fundamental
belief: doubts have been thrown on this principle only by theoretical
writers. When any deviation of structure often appears, and we see it
in the father and child, we cannot tell whether it may not be due to the
same cause having acted on both; but when among individuals, apparently
exposed to the same conditions, any very rare deviation, due to some
extraordinary combination of circumstances, appears in the parent--say,
once among several million individuals--and it reappears in the
child, the mere doctrine of chances almost compels us to attribute
its reappearance to inheritance. Every one must have heard of cases of
albinism, prickly skin, hairy bodies, etc., appearing in several members
of the same family. If strange and rare deviations of structure are
truly inherited, less strange and commoner deviations may be freely
admitted to be inheritable. Perhaps the correct way of viewing the whole
subject would be, to look at the inheritance of every character whatever
as the rule, and non-inheritance as the anomaly.

The laws governing inh