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See page in:
1859
1860
1861
1866
1869
1872

Compare with:
1859
1860
1861
1869
1872

→ Cases of special Difficulty on 1866
Special Difficulties of 1869 1872
→ for it is 1866 1872
it is 1859 1860 1861
for it is im- 1869
→ As Owen has 1866 1869
but, as Owen and others have 1859 1860 1861
OMIT 1872
→ is much analogy between them and ordinary muscles, in their manner of action, in the influence on them of the nervous power and other stimulants such as strychnine, 1866
OMIT 1872
intimate structure closely resembles that of common muscle; 1859 1860 1861
is much analogy between them and ordinary muscles, in their manner of action, in the influence on them of the nervous power and of stimulants such as strychnine, 1869
→ some believe in their intimate structure. 1866 1869
OMIT 1872
it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteuchi asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1859
it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucei asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1860
it has lately been shown that Rays have an organ closely analogous to the electric apparatus, and yet do not, as Matteucci asserts, discharge any electricity, we must own that we are far too ignorant to argue that no transition of any kind is possible. 1861
→ We 1866 1869
But this is not surprising, for we 1872
→ in all cases 1866
OMIT 1869 1872
→ these organs are; though in 1866 1869
they are. In 1872
→ an 1866 1869
as observed by Matteucci, an 1872
→ even when 1866 1869
manifests but little electricity, even when the animal is 1872
→ manifests, as lately observed by Matteucci, but little electricity; 1866 1869
OMIT 1872
→ these ends. 1866
such purposes. 1869
the above purposes. 1872
→ apparently is 1866
appears to be 1869 1872
↑ 3 blocks not present in 1859 1860 1861 1866 1869; present in 1872
It is generally admitted that there exists between these organs and ordinary muscle a close analogy, in intimate structure, in the distribution of the nerves, and in the manner in which they are acted on by various reagents. It should, also, be especially observed that muscular contraction is accompanied by an electrical discharge; and, as Dr. Radcliffe insists, "in the electrical apparatus of the torpedo during rest, there would seem to be a charge in every respect like that which is met with in muscle and nerve during rest, and the discharge of the torpedo, instead of being peculiar, may be only another form of the discharge which attends upon the action of muscle and motor nerve." Beyond this we cannot at present go in the way of explanation; but as we know so little about the uses of these organs, and as we know nothing about the habits and structure of the progenitors of the existing electric fishes, it would be extremely bold to maintain that no serviceable transitions are possible by which these organs might have been gradually developed.
→ Cases of special Difficulty on the Theory of Natural Selection.
Although we must be extremely cautious in concluding that any organ could not
possibly
....
have been produced by
successive,
successive
small, transitional
transitional
gradations,
yet,
yet
undoubtedly,
undoubtedly
grave
serious
cases of difficulty
occur.
occur,
some
some
of
of
which
which
will
will
be
be
discussed
discussed
in
in
my
my
future
future
work.
work.
One of the
gravest
most serious
is that of neuter insects, which are often
very
....
differently constructed from either the males or fertile females; but this case will be treated of in the next chapter. The electric organs of fishes offer another case of special difficulty; →for it is
possible
impossible
to conceive by what steps these wondrous organs have been
produced;
produced.
→As Owen has
remarked,
remarked,
their
there
there
→is much analogy between them and ordinary muscles, in their manner of action, in the influence on them of the nervous power and other stimulants such as strychnine,
and
and
as
as
→some believe in their intimate structure. →We do not even →in all cases know of what use →these organs are; though in the Gymnotus and Torpedo they no doubt serve as powerful means of
defense,
defence
and perhaps for securing prey; yet in the
Ray,
Ray
→an analogous organ in the
tail
tail,
→even when greatly
irritated;
irritated,
→manifests, as lately observed by Matteucci, but little electricity; so
little,
little
that it can hardly be of
any
much
much
use for →these ends. Moreover, in the Ray, besides the organ just referred to, there is, as Dr. R. M'Donnell has shown, another organ near the head, not known to be electrical, but which →apparently is the real homologue of the electric battery in the
Torpedo.
torpedo.
↑
And
And
Lastly,
lastly,
as we know nothing about the lineal progenitors of
any of
any of
these fishes, it must be admitted that we are too ignorant to be enabled to affirm that no transitions are possible, through which the electric organs might have been developed.