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We have felt the fierce play of volcanic effort, lifting new continents of opportunity from the infertile sea, without any devastation of pre-existing fields of human toil and harvest. But it still remains to elucidate the actual thing done; to reduce it to concrete data, and in reducing, to unfold its colossal dimensions.
The real difficulty in our present subject is not, as it appears to me, why domestic varieties have not become mutually infertile when crossed, but why this has so generally occurred with natural varieties, as soon as they have been permanently modified in a sufficient degree to take rank as species.
"The infertile eggs, when held before the small hole when the lamp is lighted inside the box, will look perfectly clear, same as a fresh one, while the fertile ones will show a small dark spot, which is known as the embryo. Of course, you have to learn to tell whether the embryo is living or dead, but that's easy to learn." "I think I could take care of an incubator all right," she continued.
It is in this form that the vitalizing male element meets the female infertile ovum. This mass of live and moving germs is poured all around and about the region in which the ovum lies waiting to be fertilized, and every one of them seems to be "rushing about like mad" to find what it is sent to do, namely, to meet and fertilize the ovum.
According to the general rule of pedigree-culture, the seeds of each individual plant are always saved and sowed separately. This is done even with such species as the clover, which are infertile when self-pollinated, and which are incapable of artificial pollination on the required scale, since each flower produces only one seed. My clover was always left free to be pollinated by insects.
If a male and a female, selected from each group, produce offspring, and that offspring is fertile with others produced in the same way, the groups are races and not species. If, on the other hand, no result ensues, or if the offspring are infertile with others produced in the same way, they are true physiological species.
Great cities flourished upon the banks of the Tigris and Euphrates where were the hanging gardens of Babylon and the great hunting parks of Nineveh, yet now the river runs silently between muddy banks, infertile and deserted, save for a passing nomad tribe.
On the other hand, there can be no doubt that the individuals of many natural species are either absolutely infertile if crossed with individuals of other species, or, if they give rise to hybrid offspring, the hybrids so produced are infertile when paired together.
Galton says, "I regret I am unable to solve the simple question whether, and how far, men and women who are prodigies of genius are infertile. I have, however, shewn that men of eminence are by no means so."
It is from this dreary and infertile plain that for many centuries conquering military races have poured over Europe. The climate is not so cold in winter as that of the northern part of the United States. There is much rain and the winter skies are so dark that the absence of the sun must have some effect upon the character of the people.
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