"[14]
[Footnote 14: Delafield and Prudden, "Text-Book of Pathology," pp. 62,
63.]
This modification of function among the cells which sometimes goes on in
the developing embryo, or under pathologic conditions, is very closely
analogous to the variation which goes on among species of animals and
plants. But, as we shall see later, there is a well marked limit to this
variation among species, just as we see there is in the variations among
the cells. Practically the same general laws hold good in each case.
If cells did not maintain their ancestral characters in a very
remarkable way, what would be the use of grafting a good kind of fruit
onto a stock of poorer quality? The very permanency of the grafts thus
produced is proof of the persistency with which cells reproduce only
"after their kind."
IV
How can we fail to see the bearings of these facts on the doctrine of
the transformation of species among ordinary plants and animals, which
are merely isolated and self-contained groups of cells? Do not these
facts constitute strong presumptive evidence that among animals and
plants, though there may be variation in plenty within certain limits,
perhaps within even much wider limits than used to be thought possible,
yet among these distinct organisms, little and big, new forms develop
only after their ancestral type, in full accord with the record given in
the first chapter of the Bible?
But we are now prepared to examine in more detail the facts as now known
to modern science regarding "species" of plants and animals.
Pages:
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73