A very important form of degeneration, not touched on in the text, is that exhibited in the Mexican axolotl, where the larval form of a Salamander develops generative organs, and is arrested in its further progress to the adult parental form. It is not possible to class this with the other phenomena which I have enumerated as Degeneration, since there is no modification of an adult structure, but simple arrest, and retention of the larval structure in all its completeness. I should call the phenomenon exhibited by axolotl “arrest” or “super-larvation” rather than degeneration.
The result of super-larvation is in so far similar to that of those changes to which it is desirable to restrict the term “degeneration,” that it may be classed under “simplificative evolution” as opposed to “elaborative evolution.” That there is a very real difference between super-larvation and degeneration may best be seen by taking a case of each process and instituting a comparison. Axolotl proceeds regularly on its course of development from the egg, but instead of passing from the aquatic gilled condition to the terrestrial gill-less adult form of the Salamander, it remains arrested in the earlier condition, develops its reproductive organs, and propagates itself. There is no loss or atrophy in this case, but simply a dead stop in a progressive course. On the other hand, as we have seen, the Ascidian loses, by a process of atrophy and destruction, a powerful locomotive organ, a highly-developed eye, a relatively large nervous system. The former may be compared to a permanent childishness, the latter to the second childhood, which is really atrophy and decay. It is highly probable that super-larvation has taken place at various epochs and in various groups of the animal kingdom, just as it does in axolotl, and yet we cannot hope for evidence fitted to establish its occurrence in any one case, where it is no longer possible by exceptional conditions to recover (as in the case of axolotl, which can experimentally be made to advance to the Salamander phase by proper treatment), the discarded, more developed adult form. By super-larvation it would be possible for an embryonic form developed in relation to special embryonic conditions and not recapitulative of an ancestry, to become the adult form of the race, and thus to give to the subsequent evolution of that race a totally and otherwise improbable direction.
It seems also exceedingly probable that “super-larvation” does not occur only as in axolotl through premature maturation of the reproductive organs, but the phenomenon may develop itself more slowly by a gradual creeping forward, as it were, of larval features. Just as the adaptations acquired in, and having relation to, later life tend to show themselves in an early period of the development of the individual and out of due season; so do characters acquired by the early embryo, and having relation only to this early period of life tend to remain as permanent structures, and by their invasion to perturb the adult organization. Such perturbation may tend either to simplification or elaboration.
D.
The term (degeneration of language) includes two very distinct things; the one is degeneration of grammatical form, the other degeneration of the language as an instrument of thought. The former is a far commoner phenomenon than the latter, and, in fact, whilst actually degenerating so far as grammatical complexity is concerned, a language may be at the same time becoming more and more serviceable, or more and more perfect as an organ having a particular function. The decay of useless inflexions and the consequent simplification of language may be compared to the specialization of the one toe of the primitively five-toed foot of the horse, whilst the four others which existed in archaic horses are, one by one, atrophied. Taken by itself, this phenomenon may possibly be described as degeneration, but inasmuch as the whole horse is not degenerate but, on the contrary, specialized and elaborated, it is advisable to widely distinguish such local atrophy from general degeneration. In the same way language cannot, in relation to this question, be treated as a thing by itself—it must be regarded as a possession of the human organism, and the simplification of its structure merely means in most cases its more complete adaptation to the requirements of the organism.
True degeneration of language is therefore only found as part and parcel of a more general degeneration of mental activity. To some extent the conclusion that this or that language, as compared with its earlier condition, exhibits evidence of such degeneration, must be matter of taste and open to discussion. For instance, the English of Johnson may be regarded as degenerate when compared with that of Shakspeare. There is less probability of a difference of opinion as to the degeneracy of modern Greek as compared with “classical” Greek; or of some of the modern languages of Hindustan as compared with Sanskrit, and I am informed that the same kind of degeneration is exhibited by modern Irish as compared with old Irish. Degeneration, in the proper sense of the word, so far as it applies to language, would seem to mean simply a decay or diversion of literary taste and of literary production in the race to which such language may be appropriate.
LONDON:
R. CLAY, SONS, AND TAYLOR,
BREAD STREET HILL, E.C.