Origin of Species Variorum

Comparison with 1869

Special Difficulties of the Theory of Natural Selection.

Although we must be extremely cautious in concluding that any organ could not possibly have been produced by successive transitional gradations, yet, undoubtedly, grave cases of difficulty occur, some of which will be discussed in my future work.

One of the gravest 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 im- possible to conceive by what steps these wondrous organs have been produced; but, as Owen and others have remarked, their 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, and as 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. We do not even ... 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 .. use for such purposes. 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 appears to be the real homologue of the electric battery in the torpedo. ↑ .. Lastly, as we know nothing about the lineal progenitors 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.

Cases of special Difficulty on the Theory of Natural Selection.

Although we must be extremely cautious in concluding that any organ could not .. have been produced by successive transitional gradations, yet undoubtedly serious cases of difficulty occur, some of which will be discussed in my future work.

One of the most serious is that of neuter insects, which are often .. 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 impossible to conceive by what steps these wondrous organs have been produced. As Owen has remarked, 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 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 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. ↑ 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.