| → intimate structure closely resembles that of common muscle; 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 |
| 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 |
|
| → 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 |
| OMIT 1872 |
| 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 |
| some believe in their intimate structure. 1866 1869 |
|
| ↑ 2 blocks not present in 1859 1860 1861; present in 1866 1869 1872 |
| 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 defence
and perhaps for securing prey; yet in the Ray
an
analogous organ in the tail,
even when
greatly irritated,
manifests, as lately observed by Matteucci, but little electricity;
so little
that it can hardly be of 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.
|
|
| ↑ 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.
|
|
| ↑ 1 blocks not present in 1859 1860 1861 1872; present in 1866 1869 |
| And
lastly,
as we know nothing about the lineal progenitors 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.
|
|
| → The electric organs 1859 1860 1861 |
| These same organs at first appear to 1866 1869 |
| These organs appear at first to 1872 |
|
| → which 1859 1860 1861 |
| fish, of which 1866 1869 1872 |
|
| → other. 1859 1860 1861 |
| other; but this is far from the case. 1866 1869 1872 |
|
| → lost. The presence of luminous organs in a few insects, belonging to different families and orders, offers a parallel case of difficulty. 1859 1860 1861 |
| now lost. 1866 1869 1872 |
|
| → In all these cases of two very distinct species furnished with apparently 1859 1860 1861 |
| Other cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with an adhesive gland, is apparently 1866 1869 |
| Other similar cases could be given; for instance in plants, the very curious contrivance of a mass of pollen-grains, borne on a foot-stalk with an adhesive gland, is apparently 1872 |
|
| → anomalous organ, it should be observed that, although the general appearance and function of the organ may be the same, yet some fundamental difference can generally be detected. 1859 1860 1861 |
| in Orchis and Asclepias,—genera almost as remote as is possible amongst flowering plants. 1866 1869 |
| in Orchis and Asclepias,— genera almost as remote as is possible amongst flowering plants; but here again the parts are not homologous. 1872 |
|
| → I am inclined to believe that in nearly the same way as two men have sometimes independently hit on the very same invention, so natural selection, working for the good of each being and taking advantage of analogous variations, has sometimes modified in very nearly 1859 1860 1861 |
| In all these cases of two species, far removed from each other in the scale of organisation, being furnished with a similar anomalous organ, it should be observed that although the general appearance and function of the organ may be 1866 |
| In all such cases of two species, far removed from each other in the scale of organisation, being furnished with similar anomalous organs, it should be observed that although the general appearance and function of the organ may be 1869 |
| In all cases of beings, far removed from each other in the scale of organisation, which are furnished with similar and peculiar organs, it will be found that although the general appearance and function of the organs may be 1872 |
|
