Why doesn't Ni talk about scrapping?

Because Ni's research and contribution are mainly concentrated in the field of acupuncture. Ni is a famous expert in Chinese medicine and acupuncture, and is known as the "father of modern scrapping", and has in-depth research on scrapping therapy of meridians in Chinese medicine. However, whether in his works, academic lectures or other medical papers, Ni's research and contribution are mainly concentrated in the field of acupuncture. As for the content of scraping therapy, Ni's speech or works are really rare, so Ni didn't talk about scraping.