superseded by a method of keeping records by knotting cords. A similar method of mnemonics was in use in China thousands of years ago.
In the old world before 4000 or 5000 B.C., that is to say three or four thousand years earlier, there were primitive civilizations not unlike these American civilizations; civilizations based upon a temple, having a vast quantity of blood sacrifices and with an intensely astronomical priesthood. But in the old world the primitive civilizations reacted upon one another and developed towards the conditions of our own world. In America these primitive civilizations never progressed beyond this primitive stage. Each of them was in a little world of its own. Mexico it seems knew little or nothing of Peru, until the Europeans came to America. The potato, which was the principal food stuff in Peru, was unknown in Mexico.
Age by age these peoples lived and marvelled at their gods and made their sacrifices and died. Maya art rose to high levels of decorative beauty. Men made love and tribes made war. Drought and plenty, pestilence and health, followed one another. The priests elaborated their calendar and their sacrificial ritual through long centuries, but made little progress in other directions.