of extinct Old-World apes; the more recent ancestors of this series belonged to the group of tailless anthropoid apes with five sacral vertebræ (Anthropoides), the older ancestors to the group of the tailed baboons with three or four sacral vertebræ (Cynopitheca). These four propositions are, according to our conviction, unalterably settled, no matter what further anatomical or palæontological discoveries may later do to clear up the particulars of the many steps of the phyletic evolution of man.
Comparative anatomy, which, with critical penetration, examines analytically on the one hand the structural differences of separate species of animals, and on the other systematically groups them in natural order according to their common characters, has completely demonstrated the validity of our pithecometric proposition and its significant inferences. Not less important than these morphological considerations are the physiological ones that are taught us by that instructive but hitherto, alas! too much neglected science, comparative physiology. For an unprejudiced comparison of all the activities of life teaches us that in this department also there is nowhere any radical distinction between man and apes. Our entire nutrition, secretion and circulation, breathing and digestion, are performed by the same physical and chemical processes as with the anthropoid apes. It is the same with the isolated processes of sexual activities and propagation. It is the same also for the animal functions of movement and sensation. Our mental ability results from the same physical and chemical laws as does that of the apes. The mechanics of our bony frame and the movements our muscles impart to this arrangement of levers are in no way different in man and the anthropoid apes. It was formerly thought that walking erect was a special attribute of man. We now know that this can sometimes be done by the gorilla and the chimpanzee, and especially by the gibbon.
It is quite the same with human speech. The various sounds by which apes express their sensations and their wishes, their affection, and aversion must by comparative physiology be considered as speech, just as much as are the similarly imperfect sounds that children make when learning to talk, and as the manifold tones by means of which social mammals and birds impart to each other their ideas. The modulated song of the singing bird belongs to speech just as much as the similar song of man. Besides, there exists a musical anthropoid. The singing gibbon or siamang (Hylobates syndactylus) begins with the fundamental tone E and goes upward through the entire chromatic scale, a full octave, in pure and sonorous half tones. The old doctrine that only man is endowed with speech and reason is still to-day held by some authoritative philologists, as, for example, Max Müller at Oxford. It is high time that this erroneous impression, resting on a lack of zoological information, should be abandoned.
Our pithecometric proposition met with the greatest difficulties and
