His powers of observation--upon which man in a primitive state depended almost entirely for his sustenance--were thus further strengthened by the necessity of protecting himself, so far as possible, against the uncertainties of the future. Nothing would escape him. The movement of the stars and planets, their position at different seasons and periods, the appearance of the clouds, an eclipse, the conditions of the streams, an earthquake, the direction of the winds, storms, the flight of birds, the barking of dogs, the movements of snakes and serpents, peculiar marks on the bodies of children, of adults and animals, monstrosities among mankind or the brute creation, the meeting with certain persons or animals, the rustling of leaves, the change of seasons, the lustre of precious stones, all attracted man's attention. Whatever he saw might portend something to him, in fact _did_ portend something; hence the one great aim and ideal of his life was to _see_ everything. Seeing meant foreseeing, and the man who could see everything--the _seer par excellence_, who could also understand what he saw--held in his hands the key that would unlock the secrets of the future. He possessed the means of forecasting events. Apart, then, from the interpretation of omens in connection with sacrifices and incantations, the individual had to be on the outlook at all times for signs and portents. To neglect them would entail serious consequences. This wider aspect of omens accounts for the extensive omen literature that arose in Babylonia and Assyria. Fully one-fourth of the portion of Ashurbanabal's library that has been discovered consists of omens,[548] tablets of various size in which explanations are afforded of all physical peculiarities to be observed in animals and men, of natural phenomena, of the position and movements of the planets and stars, of the incidents and accidents of public and private life,--in short, of all possible occurrences and situations. As yet but a small proportion of this literature has been published, and a thorough understanding of it is impossible until systematic publications shall have been issued. Meanwhile it is safe to assert that, as in the case of incantations and prayers, the omens were generally combined into series by the Babylonian and Assyrian scribes. Omens From Planets and Stars.