医之道下侪于艺，上通乎儒，与天地权生息之机，为国家培治与之本，责甚重焉，事甚难焉。内科然，外科
亦何独不然。余先严以儒理究心方脉，颇行世。粤孽既清后，命余旁通医术，谓可全己全人。尔时云程思渴，喜
习科举文，未遑读刀圭书，遂不果。迄今年近甲录，席帽依然，二十年来，走俗抗尘，毫无寸进，惟是间览方书，
学范文正公之存心，不取值，不夸功，求诊者亦络绎户外。至谈医则不敢知，诚重之也，诚难之也。张君贞庵，
世业儒，上承祖砚，积学能文，行医非其志，缘母氏患臀疽外症，遂习外科，虽未必擅湔肠刮骨之能，着理脑解
颅之效，而五行明理，六气辨淫，膏丹精洁，应手即瘥。董仙之名颇 ，有时采摭前贤之精义，考验心得之元微，
自成一家言，以儒为医，析理若镜，名曰《外科医镜》。谓镜吾之得失焉可，即谓镜人之死生焉亦无不可。夫秘
术不宣者，庸医之窄量也；着书行世者，良医之苦心也。张君玉字亲编，金针暗度，虽仅寸鳞片爪，而回春妙手，
已见一斑。余纵不习见张君之医，明镜不疲屡照，而即此为母学医孝也，以医济世仁也。仁孝性成，其视余之重
拂亲心。老大而仍不知医者，相去何如耶。书既成，将付剞劂，问序于余。夫余之于是科，固东坡所云扣 扪烛
者也。乌乎序！然张君既抱道而隐于医，对症检方，高悬医镜，倪日广其所传，以作救世慈航，行见消疹气之流
行，跻斯民于仁寿，必有不仅以医名世者，是编特其嚆矢焉耳。余之敏，乐援笔而为之序。
时光绪癸未季秋下浣岁进士候选训导侍生裘光照日林氏题赠
医学之道，地位低下时等同于技艺，地位崇高时可通达儒家义理。它权衡天地万物生生不息的机理，为国家培养治理的根本，责任非常重大，事务也非常艰难。内科如此，外科又怎能唯独例外呢？
我的先父以儒家道理潜心研究方剂与脉学，其著作颇受世人推崇。在平定粤地叛乱之后，他命令我旁通医术，认为这样可以保全自己并救助他人。当时我正渴望通过科举考试晋升，喜欢研习科举文章，无暇阅读医书（刀圭书代指医书），于是此事未能实现。
直到今年我已年近六十（甲录指六十岁），功名未就（席帽依然指未中举人），二十年来奔走于世俗尘网之中，毫无长进。只是偶尔翻阅医书，学习范文正公（范仲淹）存心济世的精神，不索取报酬，不夸耀功劳，前来求诊的人也是络绎不绝，门庭若市。
至于谈论高深的医理，我不敢妄言，实在是因为重视它，也深知其难。张贞庵先生，世代从事儒业，继承祖辈的书香传统，学识渊博且能写文章。行医并非他的志向，只因母亲患有臀部疽疮的外科病症，才转而学习外科。虽然未必具备“湔肠刮骨”（形容极高超的外科手术能力）的本领，或“析理脑解颅”（形容极高的解剖或治疗头面疾病的能力）的疗效，但他明辨五行之理，辨别六气之淫邪，所用的膏药丹药精纯洁净，往往一接触患处即可痊愈。
董仙的名声颇为显赫，有时采撷前贤的精义，考证心得中的微妙之处，自成一家之言。他以儒者的态度行医，剖析医理如同镜子般清晰，书名定为《外科医镜》。说它是映照我个人得失的镜子可以，说它是映照患者生死预后的镜子也不为过。
那些将秘术隐藏不宣的人，是庸医心胸狭窄的表现；著书立说流传于世的人，是良医的一片苦心。张君玉字亲自编纂此书，传授金针针灸等技法虽如“暗度陈仓”般含蓄，但仅从书中片鳞半爪的内容，已可见其妙手回春的一斑风采。
我纵然不熟悉张君的医术，但明镜不怕多次照映。仅凭他为母学医这一孝行，以及以医术救济世人的仁德，便可知晓。仁爱与孝心天性养成，他看待我违背亲心、年老仍不懂医术的态度，与我相比相差多么悬殊啊。
书既已完成，即将刻印发行，向我询问序言。对于这一科，我确实正如苏东坡所说，是“扣盘扪烛”（比喻见识片面）之人。唉！既然张君怀抱大道而隐居行医，对症选用方药，高悬医镜，相信日后会扩大其传承，作为拯救世人的慈航。必将看到消除疹气流行，使百姓达到仁爱长寿的境界，他必定不仅以医术闻名于世，这部书仅仅是个开端罢了。我欣然提笔为之作序。
时光绪癸未年（1883年）秋季最后十天，岁进士候选训导侍生裘光照日林氏题赠
The Way of Medicine, when viewed from a lowly perspective, is akin to a craft; when viewed from an elevated perspective, it connects with Confucianism. It weighs the mechanisms of life and growth between Heaven and Earth, serving as the foundation for cultivating governance in the state. Its responsibility is extremely heavy, and its tasks are extremely difficult. Internal medicine is so, and how could external medicine be any different?
My late father devoted himself to studying formulas and pulse diagnosis through the lens of Confucian principles, and his works were widely circulated. After the suppression of the rebellion in Guangdong (Yue), he instructed me to gain proficiency in medical arts, stating that this would allow me to preserve my own life and save others. At that time, I was eager to advance through the imperial examinations, preferring to study examination literature, and had no time to read medical texts (referred to as "Dao Gui Shu"). Consequently, this did not come to pass.
Until now, I am nearing sixty years old (Jia Lu refers to sixty years), yet my scholarly status remains unchanged (Xi Mao Yi Ran implies failing to pass higher exams). For twenty years, I have wandered through worldly dust without any significant progress. I merely occasionally browse medical books, emulating the mindset of Fan Zhongyan (Fan Wenzheng Gong) to maintain a benevolent heart, refusing to accept payment or boast of merits. Yet, those seeking diagnosis arrive continuously, filling the outdoors.
As for discussing medical theories, I dare not speak freely; I truly revere it and acknowledge its difficulty. Mr. Zhang Zhen'an comes from a family of scholars, inheriting ancestral scholarly traditions, accumulating learning and literary skill. Practicing medicine was not his ambition; rather, because his mother suffered from a carbuncle on her buttocks (an external condition), he turned to studying external medicine. Although he may not possess the skills of "washing intestines and scraping bones" (metaphor for highly advanced surgical capabilities) or the efficacy of "analyzing the brain and solving the skull" (metaphor for treating complex head/face conditions), he clearly understands the Five Elements (Wu Xing) and distinguishes the pathogenic influences of the Six Qi (Liu Qi). His plasters and pills are pure and clean, and diseases often heal upon application.
Immortal Dong's reputation is quite prominent. He sometimes extracts the profound essence of former sages and examines the subtleties of his own insights, forming his own school of thought. Practicing medicine with a Confucian spirit, he analyzes principles as clearly as a mirror. The book is named *Waike Yijing* (External Medicine Medical Mirror). It can be said to mirror one's own gains and losses, or even mirror the life and death of patients.
Those who keep secret techniques hidden exhibit the narrow-mindedness of mediocre physicians; those who write books for public circulation demonstrate the painstaking efforts of good physicians. Mr. Zhang Yu Zi personally compiled this work, passing on golden needle acupuncture techniques subtly. Even from just fragments of scales and claws within, one can glimpse the miracle-working hands that bring back spring (heal the critically ill). Although I am not familiar with Mr. Zhang's medical practice, a bright mirror does not tire of reflecting repeatedly. Merely by observing his filial piety in learning medicine for his mother and his benevolence in saving the world through medicine, we can see his character. Having naturally formed benevolence and filial piety, he must look down upon my failure to fulfill my parents' wishes and my ignorance of medicine despite my old age. How great is the difference between us?
Now that the book is completed and ready for printing, he asked me for a preface. Regarding this specialty, I am indeed, as Su Dongpo said, someone who "knocks on the pot and touches the candle" (metaphor for having a partial and mistaken understanding). Alas! Since Mr. Zhang embraces the Dao while practicing medicine in seclusion, selecting prescriptions according to symptoms, and holding high the Medical Mirror, I believe he will broaden his transmission in the future, acting as a boat of compassion to save the world. We shall surely see the elimination of epidemic rashes and the elevation of the people to benevolence and longevity. He will certainly be known not only for his medical skills. This volume is merely the hornet's nest (the beginning/precursor). I happily take up my pen to write this preface.
Inscribed by Qiu Guangzhao, Candidate Instructor Attendant Scholar (Sheng Shi), Juren degree holder, during the last ten days of the third month of the Guiwei year of the Guangxu reign (Autumn 1883).