Hurst concludes that: “The more the adult structure comes to be unlike
the adult structure of the ancestors, the more do the late stages of
development undergo a modification of the same kind. This is not mere
dogma, but it is a simple paraphrase of Von Baer’s law. It is proved
true not only by the observations of Von Baer and of Darwin, already
referred to, but by the direct observation of every one who takes the
trouble to compare the embryos of any two vertebrates, provided only he
will be content to see what actually lies before him and not the
phantasms which the recapitulation theory may have printed on his
imagination.”
The growth of the antlers of stags is cited by Hurst in order to
illustrate that what has been interpreted as a recapitulation may have a
different interpretation. “Each stag develops a new pair of antlers in
each successive year, and each pair of antlers is larger than the pair
produced in the previous year. This yearly increase in the size of the
antlers has been put forward as an example of an ontogenetic record of
past evolution. I, however, deny that it is such a record.”
“The series of ancestors may have possessed larger antlers in each
generation than in the generation before it. It is not an occasional
accidental parallelism between the ontogeny and the phylogeny which I
deny, but the causal relation between the two. Had the ancestors had
larger antlers than the existing ones, there is no justification for the
assumption that existing stags would acquire antlers of which each pair,
in later years, would be smaller than those of the previous year.”
Hurst concludes: “There are many breeds of hornless sheep, but they do
not bear large horns in early years and then shed them. If a rudiment
ever appears in the embryo of such sheep, its growth is very early
arrested.” The case of the appendix in man might have been cited here as
a case in point. It is supposed to have been larger in the ancestors of
man, but we do not find it appearing full size in the embryo and later
becoming rudimentary. The preceding statements will show that, while
Hurst’s view is similar in some respects to my own, yet it differs in
one fundamental respect from it, and in this regard he approaches more
nearly to the theory of Von Baer.
Public-domain text, read in full here on John Shaqi.
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