any other structure. It is only in those cases in which the modification has been comparatively recent and extraordinarily great that we ought to find the Generative Variability, as it may be called, still present in a high degree. For in this case the variability will seldom as yet have been fixed by the continued selection of the individuals varying in the required manner and degree, and by the continued rejection of those tending to revert to a former and less modified condition.
