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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1866
1872

→ does not diminish; it is even apt to increase, this being generally the result, as before explained, of too close interbreeding. 1869 1872
rarely diminishes. 1859 1860 1861
does not diminish, but is apt to increase; this increase being perhaps intelligible, as before explained, on the principles of inheritance and from too close interbreeding. 1866
→ (as will be immediately explained) 1869
OMIT 1872
so like in every respect to that of hybrids, 1866
→ when individuals belonging to 1869
OMIT 1872
of 1866
→ form are united, 1869
OMIT 1872
species (as will be immediately described), 1866
→ the above or any other view, 1869 1872
vague hypotheses, 1859 1860 1861
this or any other view, 1866
→ or constitution having 1866 1869
having 1859 1860 1861 1872
→ A 1869 1872
It may seem fanciful, but I suspect that a 1859 1860 1861 1866
→ apparently extends to 1869
extends to 1859 1860 1861 1866
holds good with 1872
→ that 1859 1860 1861 1866 1869
which I have elsewhere given, that 1872
organisation, and hence we need not be surprised that their sterility, though in some degree
vari- able,
variable,
→does not diminish; it is even apt to increase, this being generally the result, as before explained, of too close interbreeding. The above view of the sterility of hybrids being caused by two
different
different
constitutions
having been
being
compounded
confounded
into one has
lately
lately
been strongly maintained by Max
Wichura.
Wichura;
but
but
it
it
must
must
be
be
owned
owned
that
that
the
the
sterility,
sterility
sterility
→(as will be immediately explained)
which
which
affects
affects
the
the
illegitimate offspring
offspring
offspring
of
of
dimorphic
dimorphic
and
and
trimorphic
trimorphic
plants
plants,
plants,
→when individuals belonging to
the
the
same
same
→form are united,
makes
makes
this
this
view
view
rather
rather
doubtful.
doubtful.
It should, however, be borne in mind that the sterility of these plants has been acquired for a special purpose, and may differ in origin from that of hybrids.
It
must,
must
however,
also
....
be
confessed
owned
that we cannot understand,
excepting
except
....
on →the above or any other view, several facts with respect to the sterility of hybrids; for instance, the unequal fertility of hybrids produced from reciprocal crosses; or the increased sterility in those hybrids which occasionally and exceptionally resemble closely either pure parent. Nor do I pretend that the foregoing remarks go to the root of the
matter:
matter;
no explanation is offered why an organism, when placed under unnatural conditions, is rendered sterile. All that I have attempted to
show
show,
is,
is
that in two cases, in some respects allied, sterility is the common
result,—
result, —
result,—in
in
....
the one case from the conditions of life having been disturbed, in the other case from the organisation →or constitution having been disturbed by two organisations
having been
being
compounded into one.
→A similar parallelism →apparently extends to an allied yet very different class of facts. It is an old and almost universal
belief
belief,
founded,
founded
I think,
....
on a considerable body of evidence, →that slight changes in the conditions of