Since the Dutch physician, Eugen Dubois, discovered the famous remains of the fossil ape-man (_pithecanthropus erectus_) eleven years ago in Java, and thus brought to light "the missing link," a large number of works have been published on this very interesting group of the primates. In this connection we may particularly note the demonstration by the Strassburg anatomist, Gustav Schwalbe, that the previously discovered Neanderthal skull belongs to an extinct species of man, which was midway between the pithecanthropus and the true human being--the _homo primigenus_. After a very careful examination, Schwalbe at the same time refuted all the biassed objections that Virchow had made to these and other fossil discoveries, trying to represent them as pathological abnormalities. In all the important relics of fossil men that prove our descent from anthropoid apes Virchow saw pathological modifications, due to unsound habits, gout, rickets, or other diseases of the dwellers in the diluvial caves. He tried in every way to impair the force of the arguments for our primate affinity. So in the controversy over the pithecanthropus he raised the most improbable conjectures, merely for the purpose of destroying its significance as a real link between the anthropoid apes and man. Even now, in the controversy over this important ape-question, amateurs and biassed anthropologists often repeat the false statement that the gap between man and the anthropoid ape is not yet filled up and the "missing link" not yet discovered. This is a most perverse statement, and can only arise either from ignorance of the anatomical, embryological, and paleontological facts, or incompetence to interpret them aright. As a fact, the morphological chain that stretches from the lemurs to the earlier western apes, from these to the eastern tailed apes, and to the tailless anthropoid apes, and from these direct to man, is now uninterrupted and clear. It would be more plausible to speak of missing links between the earliest lemurs and their marsupial ancestors, or between the latter and their monotreme ancestors. But even these gaps are unimportant, because comparative anatomy and embryology, with the support of paleontology, have dissipated all doubt as to the _unity of the mammalian stem_. It is ridiculous to expect paleontology to furnish an unbroken series of positive data, when we remember how scanty and imperfect its material is.