Nevertheless there is little doubt that, in the main, humanity is still Yahoo-manity. Alike in mentality and in _moral_, modern man is still substantially identical with his palæolithic ancestors. He is still the irrational, impulsive, emotional, foolish, destructive, cruel, credulous, creature he always was. Normally the Yahoo in him is kept under control by the constant pressure of a variety of social institutions; but let anything upset an established social order, and the Yahoo comes to the front at once. The history of the past fifty years abundantly proves that man is still capable of atrocities equal to any in his record. Not only have we lived through the greatest political and the deadliest natural convulsion, the Great War and the Tokio earthquake, but the Russian Revolution has outdone the French and Landru the legendary Bluebeard, while for mingled atrocity and baseness the murders of Rasputin and of Alexander of Serbia are unsurpassed in history. The painful truth is that civilization has not improved Man’s moral nature. His moral habits are still mainly matters of custom, and the effect of moral theories is nugatory everywhere. Thus civilization is not even skin deep; it does not go deeper than the clothes. V Clearly it is risky to expose the inelastic nature of so stubbornly conservative a creature to new conditions at a rapid rate. He may not be able to adapt himself quickly enough, and his old reactions, which did little or no harm before, may become extremely dangerous. Yet this is just what has happened. Science has exposed the palæolithic savage masquerading in modern garb to a series of physical and mental shocks which have endangered his equilibrium. It has also enormously extended his power and armed him with a variety of delicate and penetrating instruments which have often proved edge tools in his hands and which the utmost wisdom could hardly be trusted to use aright. Under these conditions the fighting instinct ceases to be an antiquated foible, like the hunting instinct, and becomes a deadly danger. No wonder the more prescient are dismayed at the prospect of the old savage passions running amok in the full panoply of civilization! VI Nor is this the final item in our tale of woe. A third and most sinister fact which has to be faced is that Civilization, as at present constituted, is very definitely a deteriorating agency, conducing to the degeneration of mankind. This effect of Civilization is nothing new, but has been operating, it would seem, from the beginning, though not probably as intensively as now: its discovery, however, is very recent. It is quite indirect, unintended, and fortuitous, but cumulative, and in the long run has probably been a chief cause in the decay of States and civilizations, as well as an important factor in the arrest of biological development which we have had to recognize.