《黄帝内经·素问·调经论》
黄帝说：血并于阴，气并于阳，像这样血气各离其所的病证，怎样是实，怎样是虚呢？
帝曰：血并于阴，气并于阳，如是血气离居，何者为实？何者为虚？
The Yellow Emperor said: If the blood and Qi are impacted separately at the Yin and Yang parts, how can we judge whether they are solid or empty?