文中子云∶医者，意也；药者，瀹也。谓先通其意，而后用药物以疏瀹之也。善哉言乎
理在是矣，而意之通实难。泥一成之见，而欲强人之病以就吾说，其患在固执；好作聪明，
而不穷究乎古人之成书，是犹兵家之废阵图，法吏之废律令也，其患在不学。由前之说，在
不能用意；由后之说，在误于用意。夫然以不学之人，与不通不识，而又炽以忮同列，竞名
利之心，以此用药，其不致抱薪而救火，持水而投石者几何哉！语云∶学书纸费，学医人费
，盖为此也。尤君在泾，读书好古士也，而肆其力于医，于轩岐以下诸书，靡昕夕寒暑，穿
穴几遍，而以己意条贯之。其间凡有所得，笔之于书，日月既多，卷帙略定。辨五行之生克
，察四气之温严，审人事之阴阳虚实，与夫药性之君臣佐使。凡成书之沿误者，厘而正之；
古人纷纭聚讼者，折而衷之。夫惟多读古人之书，斯能善用古人之书，不误于用意，亦不泥
于用意，于长沙氏之旨，庶几得之，可谓通其意矣。抑吾观太史公之传扁鹊也，云长桑君以
禁方尽与之，忽然不见，后遂能生死人，其说近于鬼物，其人不可再得；而其传淳于意也，
谓得禁方于公乘阳庆，传黄帝扁鹊脉书五色诊病，是多读书而通于意者。扁鹊吾不得而见之
矣，得见如淳于意者斯可矣。尤君之学不知于古人何如，然多读书而通以意，是闻古人之风
而兴起者，由此书以治病，当不贻讥于人费也夫！
乾隆四年己未春三月松陵徐大椿灵胎叙
文中子说：医者的“医”，就是“意”；药物的“药”，就是“瀹”（疏通、涤荡）。意思是先要通晓医理之意，然后运用药物来疏通涤荡病邪。这话讲得好啊！道理确实如此，但真正通晓“意”却实在很难。拘泥于固定的见解，而想强行让病人的病症符合自己的说法，这种弊端在于固执；喜欢卖弄聪明，却不深入探究古人的著作，这就像兵家废弃了阵图，执法者废弃了法律条文一样，这种弊端在于不学习。按照前一种说法，问题在于不能运用心意；按照后一种说法，问题在于错误地运用心意。正因为这样，用那些不学无术的人，去对待不通晓、不认识医理的情况，再加上被嫉妒同行、竞争名利的心理所驱使，以此来用药，他们不把柴草扔进火里救火、拿着水去投石沉底的情况能有几个呢！俗话说：学书法浪费纸张，学医浪费人命，说的就是这个道理。
尤君在泾县，是一位喜爱读书、崇尚古风的士人，但他把精力倾注于医学，对于黄帝、岐伯以下的各种医书，无论早晚寒暑，都钻研得几乎遍透，并且用自己的理解将它们条理贯通。其中凡是有所心得，就记录下来写成书籍。日子久了，卷册大致定稿。书中辨析五行相生相克的规律，考察四时气候的温凉严酷，审视人事中的阴阳虚实状况，以及药物的君臣佐使配伍原则。凡是成书流传中沿袭错误的，加以整理纠正；古人之间纷繁杂乱争论不休的，加以裁断以取其中正之论。只有多读古人的书，才能善用古人的书，既不错误地滥用心意，也不拘泥于心意，对于张仲景（长沙太守）的宗旨，差不多可以领会了，可以说是通晓了医理之意。
况且我看太史公为扁鹊作的传记中说，长桑君把秘方全部给了他，忽然间就不见了，后来扁鹊就能起死回生，这种说法接近于鬼神之物，这样的人不可再得；而他为淳于意作的传记中，说淳于意向公乘阳庆获得了秘方，传授了《黄帝》《扁鹊脉书》及五色诊病之法，这是通过多读书而通晓医理之意的例子。扁鹊我已经无法见到了，如果能见到像淳于意那样的人就可以了。不知道尤君的学问与古人相比如何，但他多读书而通晓其意，这是听到古人的风范而兴起效法之心，凭借这本书来治病，应当不会被人讥笑为浪费人命吧！
乾隆四年己未年春三月，松陵徐大椿灵胎作序
Wenzhongzi said: "Yi" (medicine) is "Yi" (intent/intelligence); "Yao" (drug) is "Yue" (to dredge/cleanse). This means one must first comprehend the intent of medicine, and then use drugs to dredge and cleanse [the pathogenic factors]. How excellent this statement is! The principle is indeed correct, yet truly comprehending "intent" is extremely difficult. Clinging to a fixed view and attempting to force a patient's condition to conform to one's own theory leads to the fault of stubbornness; liking to display cleverness without thoroughly investigating the established works of ancients is like a military strategist abandoning battle formations or a legal official discarding laws and decrees, leading to the fault of ignorance. According to the former perspective, the issue lies in the inability to apply intent; according to the latter, it lies in the misapplication of intent. Therefore, employing individuals who are unlearned to handle conditions they do not understand or recognize, further fueled by jealousy towards colleagues and a competitive desire for fame and profit, when prescribing medication—how few would avoid the error of adding firewood to save a fire or throwing stones into water? As the saying goes: learning calligraphy wastes paper, but learning medicine wastes people, which refers precisely to this situation.
Mr. You, residing in Jingxian, is a scholar who loves reading and reveres antiquity, yet he devotes his efforts to medicine. Regarding various medical texts from Huangdi (Yellow Emperor) and Qibo onwards, whether morning or night, in cold or heat, he has studied them extensively, penetrating their depths, and organized them through his own understanding. Whenever he gained insights, he recorded them in writing. Over time, the volumes were largely finalized. He analyzes the generation and restriction of the Five Elements (Wu Xing), examines the warmth and severity of the Four Qi (seasonal climates), scrutinizes the yin and yang deficiency and excess in human affairs, as well as the Jun-Chen-Zuo-Shi (Sovereign-Minister-Assistant-Courier) principles of drug properties. For errors inherited in existing books, he clarifies and corrects them; for the chaotic and contentious debates among ancients, he adjudicates and finds the middle ground. Only by reading many ancient books can one skillfully utilize them, avoiding both the misuse and rigid adherence to intent. In this way, one may nearly grasp the essence of Zhang Zhongjing (of Changsha), truly comprehending the intent of medicine.
Furthermore, observing Sima Qian's biography of Bian Que, it states that Changsang Jun gave him all his secret prescriptions, then suddenly disappeared, after which Bian Que could revive the dead. This explanation borders on supernatural matters, and such persons cannot be obtained again. However, in his biography of Chunyu Yi, it states that Chunyu Yi received secret prescriptions from Gongcheng Yangqing and was taught the *Huangdi* and *Bianque Mai Shu* (Pulse Classics) along with five-color diagnosis methods. This illustrates how extensive reading leads to comprehension of intent. I cannot see Bian Que anymore, but being able to see someone like Chunyu Yi would suffice. It is unknown how Mr. You's scholarship compares to the ancients, but his practice of reading extensively and comprehending through intent shows he is inspired by the spirit of the ancients. By using this book to treat diseases, he should certainly not incur ridicule for wasting people's lives!
Preface by Xu Dachun (Lingtai) of Songling, Third Month of Spring, Jiwei Year (1739), 4th Year of Qianlong