The fall of Constantinople is generally reckoned by the historians as the starting of the Renaissance, but the greatest factor that contributed to that expansion of outlook and mentality which is so characteristic of any creative epoch, is the discovery of America in 1492. The phases of human activities are generally divisible into periods of expansion, stagnation, and contraction or decay. It is the superfluity of energy in a group that is first manifest in the restlessness that leads man to seek fair fields and pastures new. The psychological causes resulting in these more dynamic activities of human groups, far transcending previous creative that are some of the problems pursued by students of culture. True it is that the great Egyptologist Flinders Petrie, in his Revolutions of Civilizations tried to figure out a comparative chronological cycle of 1,500 years between the peak periods of the culture of any land, and the causes of such sudden bursts of activity he could only guess at as due to the arrival and assimilation of a new race. Spengler tried to arrive at a similar result by the comparative study of historical cultures in his book (marred, by its general pessimistic title and main thesis about the war) "Decline of the West." where he reduces the expansive period of a culture to a definite phase in a given zone, but fails to take note that the end of one culture is the beginning of a newer, higher, broader and deeper culture. It may be that ultimately the life of a culture will be pretty well determinable as the life of a living zygote, if culture is the product of the union biologically of favourable physical types and psycho-sociologically of stimulating idea-systems. But this point of view would leave out the fundamental facts of evolution for the culture of mankind as a whole, and ignore the fact that the culture of to-day has many things surpassing even the wildest dreams of earlier puissant peoples. Again, another recent anthropologist finds that the achievements of present civilization differ from those of the past in being more spectacular. It is only by realising that a new era dawned in the fifteenth century, which is far bigger in geographical objectivity than the culture of Greece or Rome at its highest, and the conse-
