Missouri Valley times. [volume] (Missouri Valley, Iowa) 1874-1931, 1919-05-01
LAWS Of AEREDIlf
Vital Facts Which Are Not Prop
erIy Understood.
Physical Development, More Especially
Among the Lower Animals, Largely
Matter Of Environment
In Human Family.

The laws of heredlty are not well
understood. There are many facts
pertaining to heredity which are well
known, but there are SO many excep-
tions to the rules, notlliAg in the way
of positive laws can be stated. Ac.
cording to the supposed laws of hered-
ity there should be no difference what
ever In the physical appearance of
children born of the same. parents.
And yet children born of the same
parents are never exactly alike and
frequently vary to as great degree as
II they We're not related. Not only do
they vary in physical conformation
! In shape and size-which might be
accounted for on the ground that
they were reared under different con-
ditions-but they differ frequently at
birth in the color of the hair and
eyes and disposition.
But these variations are not SO mo-
| ticeable among the wild things as
among the domestic animals and peo-
pie. There is no question as to an an
imal's being influenced in its develop
ment by reason of it's surroundings,
its exercise and It's food. And when
so influenced, it's peculiarities are
transmitted to it's offspring.
Exercise probably has more to do
with physical development of an ami
ma! than any other thing. This fact
is demonstrated in the case of per-
SONS whose ancestors have followed
single occupation for many genera
tons. In the lower animals it Is also
known to be fact that acquired
characteristics are inherited. The
bird dog inherits not only the deep
lungs acquired. by its ancestors, but
the instinct to point birds. The trot
and pace are acquired gaits with
horses and are freely transmitted
through inheritance, even to the for
nation of muscles conducive to speed.
The wild creatures do but few
things in making living. The wolf
hunts after a certain manner; the deer
grazes on the grass and buds Of
plants; the quail picks. up seeds and
bugs and worms. Over and over, gen.
Grafton after generation. these things
follow the same routine in securing
living. So they develop and transmit
to the offspring the degree of efficiency
needed to make a living. So year after
year, generation after generation, the
members of the tribe, or pack, or
flock are kept at a certain standard
and do not vary. But with domestic
animals, as where horses are used for
various purposes, where cows do not
live under Identical conditions-and
with human beings, where there are
so many ways Of making living,
variations are developed and trans
mitted to offspring.
But there are many uncertainties as
to what the offspring will be like. We
have not learned enough about the
laws Of heredity even to state posi-
lively that the offspring of famous
race horse. will have speed, although
we know that the tendency will be
toward speed. The child of we'll
! developed man and. woman may be u
weakling, although the chances are 1t
! will be strong. And certainly we do
not know that the children of very
brilliant man will be any more bril-
4 liant than other children, although
i according to the laws Of heredity, II
ought to be.