Morphine, like many prescription drugs, may require larger doses for pain control when used for extended periods of time. Over time, the body can develop a tolerance for the medication and will require more medication to experience the same level of effectiveness.
By Kimberly Munro Fri, Mar 18, 2011. The first installment of our Ancient Peru series relates what archaeology has revealed about its first cities and civilizations. The expansive, culturally rich civilizations that existed in the Americas at the time of European contact came as a great surprise to the early Spanish explorers. Most notable were the Aztec empire in Central Mexico and the Incan empire in Peru, both of which controlled great expanses of land and millions of people.
The Aztec. The last of the great MesoAmerican cultures were the Aztec, they were a Nahuatl-speaking people, who in the 15th and early 16th centuries, ruled a large empire in what is now central and southern Mexico.hen there were the Toltecs, who dominated much of central Mexico around 1200 A.D. Their language âNahuatlâ, was also spoken by the Aztecs. They were a militaristic nomadic people, and they or their ancestors may have sacked the city of Teotihuacan in 750 A.D.