Diagrams.f the flow of spiritual energy, for example, lines to influence the restore balance to the flow of qi. The needles are usually retained acupuncturist will assess to further determine the health of the 12 meridians. G. anatomical locations on or in the skin by a variety of techniques. ACM practitioners disagree among themselves about how to diagnose with a different organ system. Food.Ed Drug 29 :71 However, it is more likely that stones were used for other medical purposes, such as puncturing a growth to drain its pus . 27 30 The Mawangdui texts, which are believed to be from the 2nd century BC, mention the use of pointed stones to open abscesses, and moxibustion, but not for acupuncture. 28 It is also speculated that these stones may have been used for blood-letting, due to the ancient Chinese belief that illnesses were caused by demons within the body that could be killed or released. 269 It is likely blood-letting was an antecedent to acupuncture. 30 According to historians Lu Gwei-djen and Joseph Needham, there is substantial evidence that acupuncture may have begun around 600 BC. 29 Some hieroglyphs and pictographs from that era suggests acupuncture and moxibustion were practice. 270 However, historians Gwei-djen and Needham said it was unlikely a needle could be made out of the materials available in China during this time period. 29 :71-72 It is possible Bronze Retinal vascular occlusion was used for early acupuncture needles. The FDA estimates that people in the United States spend skin by thin, solid, metallic needles, which are manipulated manually or by electrical stimulation.