Darwin made easy / by Edward B. Aveling.

  • Edward Aveling
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: Darwin made easy / by Edward B. Aveling. Source: Wellcome Collection.

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    power of restoration. One or two special cases taken from the inferior members of the animal kingdom (I always use the rather unfortunate word “inferior” in the sense of simpler) may serve to make this general proposition more clear. In the great sub-kingdom of the ringed animals all the members have this power of restoration to a greater or less degree. Even the highest member, the lobster, of the highest class, the Crustacea, is able to reform its very large forceps- bearing limb with greater or less completeness if it is removed. In the Insecta. a class that is perhaps, on the whole, less complex than the Crustacea, the power of repara- tion is something more marked. But within the limits of this class itself, the general principle comes out. For there are three stages in the life of the insect, the larva or cater- pillar, pupa or chrysalis, the imago or perfect insect, and it is in the larval or simplest stage that the power of restoration is at its best. Parallel to this is the case of the Myriapoda, /xvpLos (murios) = many, 7rovs (pous) = a foot, a class including the centipede and the millipede. In the members of this class the restorative power, always greater than in the more complex insects, is much more noticeable up to the last moult of the skin than after that moult has taken place, and the final fixed condition of the animal has been attained. Similar phenomena are met with in the study of the highest sub-kingdom, that of the Vertebrata. In the lowest class, the Pisces, the power of reparation is most marked. The whole of the fin or limb of certain fishes has been restored after accidental removal. In the class above the Pisces, that of the Amphibia, to which the frog, the newt, the salamander belong, this capacity for reforming parts that have been taken away, is still well marked. Thus a salamander had its tail removed eight times in succession, and restored as many times. The same experiment with the leg of this amphibian was attended with similar results. The frog is clearly higher in the scale of being than the salamander. In the frog the reparative power is not nearly so evident. But in the tadpole, or flower condition of the frog, the power is possessed as completely as by the salamander, or even as by the fish. ^ And this is in keeping with the fact that the tadpole is really a fish, whilst the adult frog is really a reptile. The power
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