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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1869
1872

→ certain membrane to rupture through its own irritability, and 1866
sensation or vibration to a certain membrane which is instantly ruptured; 1869 1872
→ is 1866
of a male plant is 1869
of the male plant (for the sexes are separate in this orchid) is 1872
→ where 1866
of a female plant, where 1869
of the female plant, where 1872
→ to retain the pollen-mass, which then performs its office of fertilisation. 1866
retaining the pollen, fertilisation is effected. 1869 1872
→ and similar cases, 1866
instances, 1869 1872
→ cause of such a wide 1866
graduated 1869 1872
↑ 1 blocks not present in 1859 1860 1861 1866; present in 1869 1872
The answer no doubt is, as already remarked, that when two forms vary, which already differ from each other even in a slight degree, the variability will not be of the same exact nature, and consequently the results obtained through natural selection for the same general purpose will not be the same.
→ a long course of modification; 1866 1869
many changes; 1872
→ again. 1866 1869
again further altered. 1872
→ used, will be 1866
used, is 1869
it may serve, is 1872
→ Finally then, although 1866 1869 1872
Although 1859 1860 1861
it,
the antenna.
antenna.
This
The
antenna,
antenna
when
being
touched,
touched
transmits
causes
a →certain membrane to rupture through its own irritability, and this sets free a spring by which the pollen-mass is shot forth, like an arrow, in the right direction, and adheres by its viscid extremity to the back of the bee. The pollen-mass →is thus carried to
the
another
flower
flower,
→where it is brought into contact with the stigma, which is viscid enough to break certain elastic threads, and →to retain the pollen-mass, which then performs its office of fertilisation.
How, it may be asked, in the foregoing and in innumerable other →and similar cases, can we understand the →cause of such a wide scale of complexity and
the
of such
multifarious means for gaining the same
end.
end,
both
both
in
in
the
the
case
case
of
of
forms
forms
widely
widely
remote
remote
from
from
each
each
other
other
in
in
affinity,
affinity,
and
and
with
with
forms
forms
so
so
closely
closely
allied
allied
as
as
are
are
the
the
two
two
orchids
orchids
last
last
described?
described?
↑ It was shown, when we discussed the air-breathing apparatus of certain crustaceans, that the process of adaptation for any purpose may start from two or more forms already differing from each other to a considerable degree, and that in almost all cases the nature of the variability, on which natural selection has to work, will be different; consequently, the final structure gained through natural selection, though serving for the same purpose, will be different. We
should
must
also bear in mind that every
highly developed
well-developed
organism has
already
already
passed through →a long course of modification; and that each modified structure tends to be inherited, so that
each modification
it
will not readily be
wholly lost,
quite lost,
lost,
but may be
modified
modified
again and →again. Hence the structure of each part of each species, for whatever purpose →used, will be the sum of
the
the
many inherited changes, through which
the
that
species has passed during its successive adaptations to changed habits and conditions of life.
→Finally then, although in many cases it is most difficult
even to
to