The adaptation, however, of which there is question here is not to be confounded with the “acquired adaptation” of Lamarckian fame; for, unlike the latter, it is an inheritable modification rooted in the germ plasm. Adaptations of this sort do, indeed, adjust the organism to its external environment, but they are innate and not acquired. Hence they are often spoken of as _preadaptations_; for they precede, in a sense, the organism’s contact with the environing element to which they adjust it. They may possibly, it is true, have been acquired in the distant past, but they have now a specific germinal foundation, and no one was ever privileged to witness their initial production _de novo_. The whale, for example, though fundamentally a warm-blooded mammal, is superficially a fish, by reason of such a preadaptation to its marine environment. Preadaptation is of common occurrence, especially among parasites, symbiotes, commensals, and inquilines. Wasmann cites innumerable instances of beetles and flies so profoundly modified, in accommodation to their mode of life as guests in termite nests, that the systematist hesitates to classify them under any of the accepted orders of insects. Here the adaptive modification so disturbs the underlying homology as to make of these creatures taxonomical ambiguities. In the case of _Termitomyia_, he tells us, “the whole development of the individual has been so modified that it resembles that of a viviparous mammal rather than that of a fly.” (“The Problem of Evolution,” pp. 14, 15.) Such modifications, however, amount to major, and not merely minor, differences. We are not dealing, therefore, with varietal distinctions here, but with specific, generic, and even ordinal differences. With reference to the phenomenon of adaptive modification,[3] three things, consequently, are worthy of note: (1) it has the semblance of being adventitious to the underlying structural uniformity; (2) it is of such magnitude that it cannot be ascribed to variation within the species; (3) it has been appropriated by the hereditary process, in the sense that it is now an “inherited” character based on the transmission of specific germinal factors. [3] It may be remarked, in passing, that experimental genetics and mutation furnish no clue to the origin of adaptive characters. The Lamarckian idea alone gives promise in this direction. Orthogenesis leaves unsolved the mystery of preadaptation; yet only orthogenetic systems of evolution can be constructed on the basis of genetical facts. “Mutations and Mendelism,” says Kellogg, “may explain the origin of new species in some measure, but they do not explain adaptation in the slightest degree.” (_Atlantic Monthly_, April, 1924, pp. 488, 489.) We have seen in the previous chapter that they are impotent to explain in _any_ measure the origin of new species.