Library

The *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet) states: Among the thousands of diseases, there are no more than three categories of causes: (1) Pathogenic factors invading the meridians and entering the zang-fu organs, which constitutes the internal cause; (2) Stagnation and blockage of blood vessels in the four limbs and nine orifices, resulting from external invasion of the skin, which constitutes the external cause; (3) Injuries caused by sexual indiscretion, metal weapons, or insect and animal bites. From this detailed analysis, the origins of all diseases are fully explained. (From *Jingui Yaolue*) The second category emphasizes external causes, while regarding sexual indiscretion and dietary habits as internal causes.) Cheng Wuji of the Song Dynasty stated: There are three categories of causes for disease: (1) External causes related to Heaven, (2) Internal causes related to Humanity, and (3) Neither-internal-nor-external causes. External causes related to Heaven refer to the six excesses (Liu Yin): wind, cold, summerheat, dampness, dryness, and fire. Internal causes related to Humanity refer to the seven emotions (Qi Qing): joy, anger, worry, fear, etc., as well as improper diet and sexual fatigue. Neither-internal-nor-external causes refer to injuries from metal weapons, falls, insect/animal bites, and corporal punishment. All human diseases fall within these three categories. Shanghan (Cold Damage) is an external cause, yet the principles of the *Shanghan Lun* (Treatise on Cold Damage Disorders) comprehensively cover the six qi (wind, cold, summerheat, dampness, dryness, fire). Within it, the distinctions between exterior and interior, yin and yang, cold and heat, qi and blood, pathogenic factor and healthy qi, and deficiency and excess are thoroughly analyzed and documented. Understanding the principles of Shanghan means that the thousands of diseases do not exceed this scope. Therefore, one should begin medical studies with Shanghan, tackling the difficult aspects first, then the easy ones. Generally, diseases caused by external factors are acute and dangerous, while those caused by internal factors are slow and persistent. (Wind-stroke, malaria, dysentery, flaccidity syndrome, bi-syndrome, hernia, jue-syndrome, and various head and abdominal pains are mostly related to external causes.) Thus, a physician treating exogenous diseases can save lives or take them; a physician treating endogenous diseases may make occasional errors without immediate fatal consequences. Therefore, a physician who can treat endogenous diseases but is unfamiliar with Shanghan cannot be called a famous doctor; conversely, a physician who can treat Shanghan but is unfamiliar with endogenous diseases does not exist.

On the third, sixth, and ninth mornings of each month, I gathered my disciples to lecture on the *Huangdi Neijing* (Yellow Emperor’s Inner Canon) and the *Shanghan Lun*. After finishing the lectures, I said to the students: It is a common custom to say that practicing medicine relies entirely on fortune. I disagree. You come to study medicine; you must strive diligently in reading books and carefully investigate their principles, so as to avoid the blame of being an incompetent physician. If one relied on fortune, what profession could not be practiced? Why endure the hardships of this field! Suppose one accidentally kills an innocent person but saves hundreds; such merit cannot atone for the sin. Saving lives is the duty of a physician. Moreover, many patients have mild illnesses, some recover spontaneously, and even severe cases may be curable. Yue Ren (Bian Que) said: "I cannot bring the dead back to life, but for incurable conditions, I can restore health." This implies that diseases deemed inevitably fatal can be saved by physicians. If a patient dies not from the disease but from medical error, how is this different from killing with a club or blade? Thus, the merit of saving lives is small, while the guilt of causing harm is great. Consider Dong Feng (the Apricot Planter), who occasionally misprescribed medication, resulting in the death of a mother and child; how much more so for ordinary people? This serves as a warning to the world. Famous physicians of ancient and modern times possessed abundant vital energy in their youth; if they had continued to cultivate it, they might have achieved immortality. Alas, why did they fail? Once renowned, would they humbly learn from others? Human spirit and energy are limited; mistakes made in haste, such as incorrect prescriptions, may go unnoticed. Patients find it difficult to secure a good physician; once found, they dare not question his judgment. Even if medication errors occur, the fault is attributed to the patient's fate. Thus, minor luck leads to minor errors, while major luck leads to major errors. If students heed my words, study earnestly, their minor luck may improve, and their major errors may be avoided.

Kaizhi said: Observing physicians throughout history, some have descendants who become prominent, while others see their families decline, a difference as vast as heaven and earth. If one seeks neither fame nor profit, remains humble and receptive, and intends to save lives, how could one fail to enjoy lasting prosperity for one's descendants?

Furthermore, it was said in antiquity that physicians were called "Chancellors of the Mountains," meaning they could harmonize yin and yang, balance flavors, and hold the power of life and death. The *Book of Rites* states: "One does not take medicine from a family that has not practiced medicine for three generations." Scholar Xu interpreted this as referring to reading the classics of the Three Dynasties. I believe that inheriting a medical tradition while also studying and learning is akin to noble families where sons of scholars remain scholars. If one merely clings to ancestral prescriptions, believing them sufficient for generations, it is no different from searching for a steed according to a picture. Heaven has the qi of four seasons, and the earth has differences among five directions. Human diseases are complex and variable. Take Shanghan as an example: there are 389 methods of treatment. Can one rigidly adhere to old prescriptions and adapt to changing epidemic diseases? Zhao Kuo, who only memorized his father's writings, still suffered military defeat; how much worse for those without ancestral texts to read? Is one who inherits a grandfather's practice but refuses to learn from others comparable to Zhuge Liang in his thatched cottage? Mr. Yifangchuan said: "A physician who does not read books, even if becoming like Cang Gong or Bian Que, remains merely a technician, not a gentleman scholar." Mr. Lu Buanyuan said: "One should repeatedly reflect on these words." (Most of my disciples are children of hereditary physicians, hence I repeat this to admonish them.)