The common practice of worship of the dead prevailed also in Mexico, where its existence is attested by the preservation of the skull, or by the blocks of stone surmounted by enormous human heads which invariably denote the distinguished dead, because the gods are always represented with all their limbs. There was also a large heavenly hierarchy, gods of the atmosphere and stellar powers, some being associated with particular mountains, but the most important of all was Tezcatlipoca the giver and sustainer of life, the symbol of the wind, the bestower of life and death. Next to him came the sun god, Huitzilopochtli. He being a living person was, as appeared from the natural phenomena seen in the succession of the seasons and the change from day to night, especially in need of food. His vitality frequently shows signs of failing. It is therefore especially incumbent upon man to help him in this struggle for existence. So necessary was the maintenance of this principle of religious faith that the sun always received a share of the human victims offered to the other divinities. But all sorts of vegetable and animal life were offered to this needy divinity, who seemed to the Mexicans to show such constant signs of an impaired vitality. In the pictures of the Aztecs the rays of the sun, significantly represented as long crimson tongues licking up blood, constantly appear. The order of society was so regulated as to keep the sun in full vigorous condition; hence the never ending slaughter of human victims supplied by incessant warfare with neighboring tribes to provide the food supply for the sun. If there had been large animals in Mexico, these ghastly immolations of human victims might not have stained the progress of the Aztec people, for it is an established principle that the search for food is closely related to the development of religion among primitive races.