Modern medicine is a wonderfully complex field of study, with several advances in both its theoretical and practical aspects being made everyday. In light of the pride modern physicians and scientists take in their vast knowledge, it is important to remember how far we have come throughout history. Many civilizations and cultures around the world have made essential contributions to medicine, both great and small, but no one can deny the impact both ancient Chinese and Islamic medical and alchemical practices have had on modern medicine. Qi was the central principle behind Chinese correlative thought, and it was believed to be the one thing that drove human life, as it occurred everywhere. Written texts took an increasingly more prominent role in the transmission of knowledge, and in no time at all, the educated yi ("physician") emerged. Other noteworthy contributions include an early conceptualization of the circulatory system, the development of pharmacies, the establishment of proper medical school systems, and the emergence of a set of standard hygienic practices that would allow people to take responsibility for their own health. The scholars of the Islamic Golden Age, for the most part, seemed to decry the mixing of the occult with science, and therefore sought to draw a clear distinction between alchemy (by limiting its application to the transmutation of metals) and what they deemed "real" science. Notable contributions of Arab-Islamic scientists include the pioneering of a hospital prototype, along with the development of the science of chemistry and the introduction of the experimental laboratory as the birthplace of new scientific knowledge. The important question that has yet to be answered is how extensive the connection was between the Chinese and Arab worlds. Trade was thriving during the medieval period, and so it is not wrong to assume that the exchange of goods would go hand-in-hand with the exchange of knowledge. We may never fully know exactly what happened, but further research on this topic may eventually bring an answer to light.