Further, as stated in a previous chapter, Pictet catalogues ninety-eight species of mammals which inhabited Europe in the Post-glacial period. Of these fifty-seven still exist unchanged, and the remainder have disappeared. Not one can be shown to have been modified into a new form, though some of them have been obliged, by changes of temperature and other conditions, to remove into distant and now widely separated regions. Further, it would seem that all the existing European mammals extended back in geological time at least as far as man, so that since the Post-glacial period no new species have been introduced in any way. Here we have a series of facts of the most profound significance. Fifty-seven parallel lines of descent nave in Europe run on along with man, from the Post-glacial period, without change or material modification of any kind. Some of them extend without change even farther back. Thus man and his companion-mammals present a series of lines, not converging as if they pointed to some common progenitor, but strictly parallel to each other. In other words, if they are derived forms, their point of derivation from a common type is pushed back infinitely in geological time. The absolute duration of the human species does not affect this argument. If man has existed only six or seven thousand years, still at the beginning of his existence he was as distinct from lower animals as he is now, and shows no signs of gradation into other forms. If he has really endured since the great Glacial period, and is to be regarded as a species of a hundred thousand years' continuance, still the fact is the same, and is, if possible, less favourable to derivation.