We have here evidently a process corresponding to the
fertilization of the egg in higher animals; yet there is no egg,
spermatozoon, or sex.
It is a little mass of protoplasm containing a nucleus, and
corresponds, therefore, to one of the cells, most closely to the
egg-cell or spermatozoon of higher animals. If every living being is
descended from a single cell, the fertilized egg, it is not hard to
believe that all higher animals are descended from an ancestor
having the general structure or lack of structure of the amoeba.
But is the amoeba really structureless? Probably it has an
exceedingly complex structure, but our microscopes and technique are
still too imperfect to show more than traces of it. Says Hertwig:
"Protoplasm is not a single chemical substance, however complicated,
but a mixture of many substances, which we must picture to ourselves
as finest particles united in a wonderfully complicated structure."
Truly protoplasm is, to borrow Mephistopheles' expression concerning
blood, a "quite peculiar juice." And the complexity of the nucleus
is far more evident than that of the protoplasm. Is protoplasm
itself the result of a long development? If so, out of what and how
did it develop? We cannot even guess. But the beginning of life may,
apparently must, have been indefinitely farther back than the
simplest now existing form.
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