But like I've said: I've read this once on a skeptic blog and heard it repeated possibly by another reader thereof but I've never seen a citation for this and it may be smug western bullshit meant to portray China as cynical. IDK.
the assassination of President McKinley only succeeded after weeks of lingering infection because "the best surgeons in the country" kept putting their fingers into the bullet wound
My point here is not the technical content of the Chinese practices, but rather the arrogance and military-style dismissal of alien techniques and knowledge.