Library

I have often said that the creative forces of nature are the masters of all things; the ruler is the master of the Three Powers (Heaven, Earth, and Humanity); the official in charge of textual verification is the master of literature; the general is the master of the three armies; and medicine, furthermore, is the master of everyone from the Son of Heaven down to the common people. Is not the relationship involved here profound? Therefore, former Confucian scholars stated: "If one does not understand the Five Movements and Six Qi (Wuyun Liuqi), what use is it to search through all medical books? If one does not understand the Twelve Meridians, every opening of the mouth and movement of the hand will be erroneous." Sun Simiao also said: "One who does not understand Yin and Yang cannot be called a Grand Physician." These words are truly insightful; they are indeed matters that those engaged in this profession should study with deep concentration.

I alone find it strange that contemporary physicians lack clarity in perceiving principles at the outset and possess no skill in adapting to changes by the end. Those pursuing bizarre and unconventional methods may admire ancient theories while neglecting practical applications; those confined to the *Ju Fang* (Formulary) texts may cite one aspect while discarding hundreds of others. In the balance between deficiency and excess, and in the application of tonification and purgation, errors of a hair's breadth can lead to deviations of a thousand li, causing significant harm to patients. The reasons for this are that their investigation is not precise, their embodiment and practice are not mature, and their knowledge and experience are not extensive enough.

Mr. Xu Donggao of Xin'an has devoted himself to this path for nearly thirty years, saving countless lives. He once told me: "The essence and profound secrets of medicine are fully contained in the *Neijing* (Inner Canon). Since then, individuals have differed and eras have changed; although there are many schools and paths, none can ultimately transcend this foundation. It is like how all towering forms are mountains, yet Mount Tai is their patriarch; all flowing forms are water, yet the vast ocean is their source. However, unless one comprehensively surveys antiquity, cross-references various schools, and searches widely for corroborating evidence, how could one know the excellence of the *Neijing* in integrating and organizing all threads? This is why the compilation of the *Yitong* (Medical Unity) was indispensable."

Upon reading it, I found its structure clear and analysis detailed, with arguments balanced according to context. It acts like the cord in a net or the collar on a fur coat, allowing students to avoid confusion and disorder in a single step. Thus titled *Gujin Yitong* (Comprehensive Medical Unity through the Ages), it truly synthesizes the similarities and differences of a hundred schools and continues the orthodox lineage of Huangdi and Qibo. One might even say that outside of this book, there is no other medicine. Just as Confucius synthesized the greatness of the sages, and Zhu Xi synthesized the greatness of the Confucian scholars, Mr. Xu can be said to have synthesized the greatness of physicians. Thus, his merit in elevating the world and its people to an era of spring-like peace and longevity is indeed magnificent!

Nevertheless, lower learning can be transmitted through words, but higher understanding must be realized through the mind. Mr. Xu gained fame in the capital for his mastery of medicine, rivaling Bian Que and Qin Yueren, surpassing Liu Juanzi and Zhang Zhongjing, achieving efficacy regardless of difficulty or ease, because the subtlety of application lies within the heart. The *Yitong* is merely a byproduct of this mastery. This depends on the self-realization of the learner. What do those who understand speech think of this?

Written by Tang Shilong, Marquis of Lingbi, Grand Tutor to the Crown Prince, General Officer Guarding Huai'an, and Commissioner-in-Chief of Grain Transport under Imperial Commission.