individual, the germ cells are
so completely isolated from the growing organism that nothing but
nourishment in the shape of blood can possibly reach them, hence they can
be affected only by a vitiated or poisonous blood supply. It seems to be
true, therefore, that only the old, deeply-impressed traits, capacities,
or racial characters can be inherited. This is, no doubt, the chief secret
of the power of heredity to breed true.

It has been a popular belief that if parents acquired skill in music,
mathematics, or special ability in any other particular that such ability
could be imparted to their children, but in the light of the above facts,
this appears to be impossible. Of course, if such ability is a slumbering,
inborn trait of either parent, or of some immediate ancestor, the ability
might be transmitted.

It is reasonable to suppose, however, that any acquired trait or ability
of the parent, if practised and continued steadily by his children and
their descendants for many generations, will come to be an inborn trait
or character capable of being transmitted. Otherwise, it is extremely
difficult to understand how the human family can progress and become
permanently improved.

_Galton's_ law is believed to be approximately correct. It may be stated
as follows: Children inherit on the average one-half their characteristics
from parents, one-fourth from grandparents, one-eighth from
great-grandparents, and so on in ever diminishing ratio to remote
ancestors. But owing to the fact that some inheritable traits or
characters are likely to be dominant and others recessive, Galton's law
must be modified, so that only under the most favorable conditions can it
be regarded as reliable.

Owing to the fact that the primary elements or traits of character
contributed by each parent may combine in many ways in the embryo,
considerable variation in the children of the same parents is
inevitable--one child may resemble the father, another the mother, and
yet another some near ancestor. Variability is, therefore, the rule among
offspring in the same family, and in some instances it is decidedly
pronounced, but in all cases, the variation must be confined to the
possible combinations of characters transmitted from parents and ancestors.

_The law of regression_ represents the tendency of the extreme elements of
the race constantly to seek the middle or mediocre level. For example, the
children of superior parents are not like