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Their new theory is only a slight modification of an old one, or the old adage, omne vivum ex ovo all life is from an egg. For they assert that every living thing primordially proceeds from an ovule in protoplasm, the essential part of the protoplasmic egg, so to speak, being this little ovum or cellule, from which have issued all possible organisms in both the vegetable and animal kingdoms.
Whether species have often or ever been modified through this comparatively sudden mode of transition, I can form no opinion; but if this has occurred, it is probable that the differences between the young and the mature, and between the mature and the old, were primordially acquired by graduated steps.
We have formerly seen that parts many times repeated are eminently liable to vary in number and structure; consequently it is quite probable that natural selection, during a long-continued course of modification, should have seized on a certain number of the primordially similar elements, many times repeated, and have adapted them to the most diverse purposes.
If we consider leaf-climbers alone, the idea that they were primordially twiners is forcibly suggested. The internodes of all, without exception, revolve in exactly the same manner as twiners; some few can still twine well, and many others in an imperfect manner. Several leaf-climbing genera are closely allied to other genera which are simple twiners.
An egg is, as already said, a conception exposed beyond the body of the parent, whence the embryo is produced; a conception is an egg remaining within the body of the parent until the foetus has acquired the requisite perfection; in everything else they agree; they are both alike primordially vegetables, potentially they are animals.
With respect to the mammae of the higher animals, the most probable conjecture is that primordially the cutaneous glands over the whole surface of a marsupial sack secreted a nutritious fluid; and that these glands were improved in function through natural selection, and concentrated into a confined area, in which case they would have formed a mamma.
He tamed certain animals, he developed his primordially haphazard agriculture into a ritual, he added first one metal to his resources and then another, until he had copper and tin and iron and lead and gold and silver to supplement his stone, he hewed and carved wood, made pottery, paddled down his river until he came to the sea, discovered the wheel and made the first roads.
We have formerly seen that parts many times repeated are eminently liable to vary in number and structure; consequently it is quite probable that natural selection, during a long-continued course of modification, should have seized on a certain number of the primordially similar elements, many times repeated, and have adapted them to the most diverse purposes.
Yet if our analysis does not lead us astray, the theory of Democritus was not truly monistic; his indestructible atoms, differing from one another in size and shape, utterly incapable of being changed from the form which they had maintained from the beginning, were in reality as truly and primordially different as are the primordial elements of Anaxagoras.
Starting, then, with these data, matter, force, and the law of gravitation, what must happen? We have the strongest scientific reason to believe that the matter of the solar system primordially existed in a highly diffused or nebulous form. By mutual gravitation, therefore, all the substance of the nebula must have begun to concentrate upon itself, or to condense.
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