What sense then is there in making such a fuss about the present crisis? It is a particularly plain case of the perennial choice of Hercules. What is needed is just a little clear thinking and plain speaking to a society more than usually debauched by a long regime of flattery, propaganda, and subterfuge. Mankind _can_ make a fool of itself, as it always could; if it does, its blood will be on its own head. For it has knowledge enough to avoid the dangers that threaten it, if it will use its knowledge properly. II The first fact to be enunciated plainly, and faced, until it grows familiar, and its import is appreciated, is that, biologically speaking, Man has ceased to be a progressive species long ago. The evolutionary impetus which carried our ancestors from the level of the ape or even of the lemur, through such subhuman types as _Pithecanthropus_, and the Heidelberg and Neanderthal men, to ‘modern’ man, seems to have spent itself by the middle of the palæolithic period, _i.e._ say, thirty thousand years ago. At any rate, the Cro-Magnon people of the Aurignacian age, who then appeared upon the scene, were in no wise inferior to any subsequent race of men, either in stature or in brain capacity. They average six feet three inches in height, with one-sixth more brains than the modern European. So far indeed as their physical remains can indicate, they seem to have been very definitely the finest race of human beings that has ever existed. If we have improved on them, it has probably been only in such minor matters as resistance to the microbes of the many diseases which flourish among dense populations under slum conditions. Against that probability have to be set such certainties as that our toes and many of our muscles are being atrophied and that we are getting more liable to caries and baldness. This remarkable fact of the arrest of his biological development is certainly the greatest mystery in the history of Man. It at once raises two further questions: In the first place, how did it happen, and what caused it? And, secondly, what has enabled man, nevertheless, to progress in other respects, in knowledge, in power, and in culture?