Researchers analyzing microscopic residues on Ming dynasty-era surgical instruments report evidence consistent with the controlled topical application of a highly toxic chemical used as an anesthetic. The findings come from surgical scissors and tweezers recovered from a tomb dated to the 14th to early 15th century (1348–1411 CE) in Jiangyin, China. Using chemical and residue analysis, the teams identify traces on the tools that they interpret as the first direct evidence of an anesthetic effect from this period, rather than incidental contamination. Both outlets describe the chemical as derived from a toxic plant used in traditional Chinese medical practice, and they characterize the pattern of residues as indicating deliberate, localized use on instruments, which implies a degree of control in application. The researchers conclude that the discovery adds to historical understanding of medical sophistication during the Ming dynasty and extends the timeline for chemical evidence of topical anesthetics. The report emphasizes that the evidence is based on tool residue analysis, which reconstructs past use through chemical traces rather than direct observation.