The Washington times., 1916-01-05

M in breeding stock and in
IVY raising crops is based upon
verys important law of
heredity, which, for example. explains
the presence of color in flowers and in
the hides OF horses.
Gregory Johann Mendel, the discov-
erer of this curious regulation Of her
eaity. was a Bohemian monk and alb
bntt. who made experiments in 1855
which reNolutionized biology.
MenJePs wonderful and now veri-
fed experiments remained unknown
until 1900, when an account of them
was unearthed in an obscure scientific
journal, Proceedings Of the National
History Society of Brunn." At the
same time attention was called to FIR.
botanists, De vries. Tschermak, and
Correus. Experimental workers had
not yet tackled the problems Of her
edity, and "genetics." as It Is called,
was not even in mind.
Mendel took the common garlen
pea for his experiments. This plant is
easily cultivated and produces several
generations in a year. 1t has several
races. or pure lines" and also has
conspicuous characters, such as defin-
lures of the garden pea yield three
generations. the different strains hav-
ing red. white or purple flowers. The
seeds are wrinkled or smooth and the
bushes are dwarfs or giants in size.
How Mendel Worked.
To investigate the laws of heredity,
not only must such distinctive an iso-
lated characters be kept in mind. but
the observations must be kept clear eX-
actly as to how much each parent con-
tributes to the offsprings' characters.
This holds for man, animal, Towering
plant or fungus. To avoid the difficulty
of parents with similar characters, a
hybrid is best for experimental pur-
poses. In this way the differences be-
tween the parents are brought out in
sharp contrast in the progeny. When
Mendel crossed purple-fowered pea
with peas that had white blossoms. the
ensuing generation at once emphatically
esta blished the quota of each parents
contribution in colored flowers.
The mating of hybrids Ia to gene
tics" what the microscope Is to other
sciences in that II makes facts so dra
matically plain that those who wilfully
shut their eyes to the truth dare not
deny it. Moreover. the laws of heredity
made thus evident apply with equa
certainty to inheritance by non-hybrids
! that is to say. similar parents. Briefly
what is discovered 10 be inherited ir
one kind OF mating or crossing will he
| found likewise true of inheritance ir
general.
The various races of garden pea.
which Abbot Mendel selected were pos.
sessed OF SO many characters and pos.
sibilities that they might have confused
any Investigator less skillful He die
| not divide his powers. however. but
gave strict heed through successive
| generations to only one character at g
time.
First Mendel followed the color OF
flowers. Then their height or small
| ness! was observed. To make the
classic tale short. what he found fol-
one character also held for the others
He brought to light the fact that il
| makes no difference in inherited char.
| acterlstics, whether they came from the
| father or the mother.
Where Whiteness "Goes."
He used the male purple flower tc
! cross with a white cne. and Vice verIa
| The progeny cf both matinGs were pur
pie This means that the purple factor
i'll Towers dominates white in the ne%
generation. In SenetiCs this is called
.,hs brid seneratinn." The "ssertia
one parent is white. all the "childrcn'
are purple What has become CT Tho
| "whiteness?'
"Whitencss" will be discovered agair
in the randchildrer' when 'he pur
pie lowered plants are crossed Will
''whitencss' Is not gone. bat has oul!
been suppressed or temporarily ostra
! cized
Most colors OF hair. eyes and fur il
| white Grays are sometimes mixed, ant
| are not unit characters" in hercdity
as are legion of Inherited characters
| tics.
| The law of heredity. however. I,
which this all applies. really aprears il
| Grafton of grandchildren - the frs
! pair has three kinds. In every fcu