All the essential features of the brain of modern man are to be seen in the brain cast. There are some which must be regarded as primitive. There can be no doubt that it is built on exactly the same lines as our modern brains. A few minor alterations would make it in all respects a modern brain.... Although our knowledge of the human brain is limited--there are large areas to which we can assign no definite function--we may rest assured that a brain which was shaped in a mould so similar to our own was one which responded to the outside world as ours does. Piltdown man saw, heard, felt, thought, and dreamt much as we do still. And this was 150,000 years ago at a modern estimate, and some would say half a million. There is neither agreement nor certainty as to the antiquity of man, except that the modern type was distinguishable from its collaterals hundreds of thousands of years ago. The general impression left is very grand. In remote antiquity the Primate stem diverged from the other orders of mammals; it sent forth its tentative branches, and the result was a tangle of monkeys; ages passed and the monkeys were left behind, while the main stem, still probing its way, gave off the Anthropoid apes, both small and large. But they too were left behind, and the main line gave off other experiments--indications of which we know in Java, at Heidelberg, in the Neanderthal, and at Piltdown. None of these lasted or was made perfect. They represent _tentative_ men who had their day and ceased to be, our predecessors rather than our ancestors. Still, the main stem goes on evolving, and who will be bold enough to say what fruit it has yet to bear! [Illustration: _After a model by J. H. McGregor._ PROFILE VIEW OF THE HEAD OF PITHECANTHROPUS, THE JAVA APE-MAN--AN EARLY OFFSHOOT FROM THE MAIN LINE OF MAN'S ASCENT The animal remains found along with the skull-cap, thigh-bone, and two teeth of Pithecanthropus seem to indicate the lowest Pleistocene period, perhaps 500,000 years ago.] [Illustration: _From the reconstruction by J. H. McGregor._ PILTDOWN SKULL. THE DARK PARTS ONLY ARE PRESERVED, NAMELY PORTIONS OF THE CRANIAL WALLS AND THE NASAL BONES Some authorities include a canine tooth and part of the lower jaw which were found close by. The remains were found in 1912 in Thames gravels in Sussex, and are usually regarded as vastly more ancient than those of Neanderthal Man. It has been suggested that Piltdown Man lived 100,000 to 150,000 years ago, in the Third Interglacial period.] [Illustration: _Reproduced by permission from Osborn's "Men of the Old Stone Age."_ SAND-PIT AT MAUER, NEAR HEIDELBERG: DISCOVERY SITE OF THE JAW OF HEIDELBERG MAN _a-b._ "Newer loess," either of Third Interglacial or of Postglacial times. _b-c._ "Older loess" (sandy loess), of the close of Second Interglacial times. _c-f._ The "sands of Mauer." _d-e._ An intermediate layer of clay.