But that is a metaphysical matter, with which we need not concern ourselves in this discussion; the important point is that among the everyday happenings of life are processes that are quite competent to account for the condition of adaptation exhibited by various animal forms. These processes are real and natural, not imaginative or artificial, and so they will remain even though it will become clear that much is still to be learned about the causes of variation and the course of biological inheritance. Darwin was the first to contend that natural selection is but a part of nature's method of accomplishing evolution. As such it is content to recognize variations and does not concern itself with the origin of modifications; it accepts the obvious fact that congenital variations are inherited, although it leaves the question as to how they are inherited for further examination. Because the doctrine of natural selection does not profess to answer all the questions propounded by scientific inquisitiveness, it must not be supposed that it fails in its immediate purpose of giving a natural explanation of how evolution may be partly accounted for. * * * * * Before proceeding to the post-Darwinian investigations that have done so much to amplify the account of natural evolution, let us consider the contrasted explanation given by Lamarck and his followers. As we have stated earlier, Lamarckianism is the name given to the doctrine that modifications other than those due to congenital factors may enter into the heritage of a species, and may add themselves to those already combined as the peculiar characteristics of a particular species. Let us take the giraffe and its long neck as a concrete example. The great length of this part is obviously an adaptive character, enabling the animal to browse upon the softer leafy shoots of shrubs and trees. The vertebral column of the neck comprises just the same number of bones that are present in the short-necked relatives of this form, so that we are justified in accepting as a fact the evolution of the giraffe's long neck by the lengthening of each one of originally shorter vertebrae. The Lamarckian explanation of this fact would be that the earliest forms in the ancestry of the giraffe as such stretched their necks as they fed, and that this peculiar function with its correlated structural modification became habitual. The slight increase brought about by any single individual would be inherited and transmitted to the giraffes of the next generation; in other words, an individually acquired character would be inherited. The young giraffes of this next generation would then begin, not where their parents did, but from an advanced condition. Thus, by continued stretching of the neck and by continued transmission of the elongated condition, the great length of this part of the body in the modern giraffe would be attained.