The paper now presented records the results of such a detailed
experiment. This experiment was practically confined to a small
plant group, and is now after eight years' pursuit concluded in all
essentials. Whether the plan upon which the separate experiments
were conducted and carried out was the best suited to attain the
desired end is left to the friendly decision of the reader.
[Footnote 17: The Production of Hybrids in the Vegetable Kingdom.]
{208}
Mendel's discoveries with regard to peas and the influence of heredity
on them, were founded on very simple, but very interesting,
observations. He found that if peas of different colors were taken,
that is to say, if, for instance, yellow-colored peas were crossed
with green, the resulting pea seeds were, in the great majority of
cases, of yellow color. If the yellow-colored peas obtained from such
crossing were planted and allowed to be fertilized only by pollen from
plants raised from similar seeds, the succeeding generation, however,
did not give all yellow peas, but a definite number of yellow and a
definite number of green. In other words, while there might have been
expected a permanence of the yellow color, there was really a
reversion in a number of the plants apparently to the type of the
grandparent. Mendel tried the same experiment with seeds of different
shape. Certain peas are rounded and certain others are wrinkled. When
these were crossed, the next generation {209} consisted of wrinkled
peas, but the next succeeding generation presented a definite number
of round peas besides the wrinkled ones, and so on as before. He next
bred peas with regard to other single qualities, such as the color of
the seed coat, the inflation or constriction of the pod, as to the
coloring of the pod, as to the distribution of the flowers along the
stem, as to the length of the stem, finding always, no matter what the
quality tested, the laws of heredity he had formulated always held
true.
What he thus discovered he formulated somewhat as follows: In the case
of each of the crosses the hybrid character, that is, the quality of
the resultant seed, resembles one of the parental forms so closely
that the other escapes observation completely or cannot be detected
with certainty. This quality thus impressed on the next generation,
Mendel called the dominant quality. As, however, the reversion of a
definite proportion of the peas in the third generation t
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