576 inventions: The Americas women Games like hackey sack and various forms of kickball were played by teams of Plains Indian women strenuously competing for accolades and prizes Inventions that might be more readily associated with Asia, Europe, and Africa were sometimes developed separately in the Americas The abacus, a counting machine usually attributed to the Chinese, was used by both Mayan and Aztec mathematicians Similarly, various sleds, snowshoes, and toboggans developed by Arctic American peoples had their analogues in other parts of the world The sled pulled by teams of trained dogs remains a uniquely American vehicle Because riders of these sleds could become snow-blind on their long journeys across white expanses, Indians of those climes devised goggles to cut down on the glare from the snow The goggles fit over the eyes and let light through only a long, narrow slit Another ingenious Arctic American invention was the bow drill This small tool consisted of a string looped around a friction stick, and it was used to start fires with the rapid back and forth motion of the stick being turned by the string Bow drills could also function like early power tools, in that they enabled the user to rapidly make holes in other tools and weapons The Maya used bow drills in sculpture and even in dental procedures In the field of weaponry South American warriors developed an impressive array of projectiles Amazonian Indians possessed a frightening arsenal of poisoned blow darts, which, fortunately for their enemies, they used mostly on birds, monkeys, and other prey high in the rain forest canopy Besides the standard arrows, spears, clubs, maces, and fighting sticks, soldiers in the Andes and southern South America used bolas to fell or strangle their adversaries or prey These stones on strings opened like propellers when flying through the air but then rapidly tangled once they hit the legs, arms, or necks of their intended victims Bolas were made famous by Argentine gauchos in later colonial history Inca warriors also heated stones until they glowed red, wrapped them in tarred cloths (which caught on fire), and hurled them at their enemies The detrimental effect of these burning missiles was equaled only by their fearsome appearance raining through the air like meteorites With their invention of metal casting in ancient times, the Andeans might have ensured that they had among the hardest and sharpest weapons used in close combat However, Andeans used their metallurgy mostly to produce art, not weaponry In any case, the Aztec battle-ax would have surpassed any metal implement the Inca could make since it was edged with obsidian, a hard volcanic glass that could be more than razor sharp In the Great Basin states of Idaho, Oregon, Utah, and Wyoming, preconquest Indians devised a bow laminated with animal sinew that greatly increased the tensile strength of the weapon This bow sent arrows flying as much as twice the distance of enemy arrows Many scientific and medical innovations arose from the Americas following the beginning of the Common Era While Native North Americans developed a wide range of antibacterial and antiviral medicines, Mesoamericans created a system of vigesimal math, mathematics based on cycles of 20 rather than 10 that fostered increasingly complex astronomical and calendrical computations Advanced obstetrical practices were developed, probably based on already sophisticated ancient techniques Prenatal care, methods of inducing labor, gravity-assisted birthing, sedation and pain killing, regulation of uterine bleeding, and induced expulsion of the placenta were part of North, Central, and South American obstetrics Additionally Mesoamericans had techniques for correcting breech presentations and even performing cesarean sections Central and South Americans developed several tools to aid in their medical procedures For instance, the Inca created stretchers for carrying disabled patients, and both the Aztec and Inca developed surgical forceps for removing bone fragments In fact, such forceps may have been used in brain surgery, a technique independently invented in several American native societies and known to have been performed in triage conditions after warfare Aztec surgeons also attached wooden nails deep into the center of broken bones that were difficult to reset In a unique use of unmodified natural tools, Amazonians used the jaws of large leaf-cutter ants as surgical staples to close wounds The insects were held and made to bite the opposite edges of the patient’s wound so that their strong jaws would contract and close the laceration Once these powerful pincers were locked in place, the surgeon killed the ant, breaking off his body and leaving the locked jaw in place as a surgical staple These natural clasps were removed once the wound had healed Much of preconquest American medical knowledge seems clustered around emergency and obstetric procedures However, a wide range of preventive medicines, quarantines, holistic health foods and herbs specifically chosen for the patient, and even plastic surgery and talk therapy were practiced by the Aztec and some North American Indians, including the Chippewa and the Iroquois Among the medicines invented or discovered by Native Americans in the preconquest Common Era were quinine from the bark of the quina (cinchona) tree, used by the Andeans to treat fevers (and later malaria in the colonial period); coca, primarily used by Andean workers as a stimulant to increase resistance to fatigue and cold but also used as an anesthetic in surgery; stone seed and dogbane, used by the Sho-