Aztec zodiac man, facsimile of original painting or codex. Medical astrology is an ancient medical system that associates various parts of the body, diseases, and drugs as under the influence of the sun, moon, and planets, along with the astrological signs. Each of the astrological signs is associated with different parts of the human body. The Aztec calendar is also called by name of Tonalpohualli. There is a division between the goddesses and the gods, that gives a special meaning to every single day of the Aztec calendar. There are 20 different glyphs of the Aztec signs that are ruled by a certain god or goddess that has influence over an individual's behavior. The Aztec had a well established birth sign structure, much like modern astrology. Babies born during certain days were expected to develop into sickly children and die early of disease. Conversely babies born on other days could expect favor from the gods and live happy, disease free lives. Should one of these favored people develop illness, he or she surely must have forgotten to properly pay homage to the gods. Published: R. Havell & Colnaghi London, 1831.