医之有《本经》也，犹匠氏之有绳墨也。有绳墨而后有规矩，有规矩而后能变通。变通
生乎智巧，又必本诸绳墨也。原夫炎帝《本经》，绳墨之创始也。《大观》、《证类》，规
矩之成则也。濒湖《纲目》，成则中之集大成，未能达乎变通也。譬诸大匠能与人规矩，不
能与人智巧。能以智巧与人达乎变通之道者，黄帝《灵》《素》之文也。能以炎黄之道随机
应用，不为绳墨所拘者，汉长沙一人而已。长沙以天纵之能，一脉相承炎黄之道，信手皆绳
墨也。未闻炎黄而外别有绳墨也。尝思医林学术，非不代有名人，求其端本澄源，宗乎《本
经》主治者，《玉函金匮》而外未之闻也。长沙已往，唐逸士《千金方》独得其髓，其立方
之峻，有过于长沙者，后世末由宗之。以故集本草者，咸以上古逆顺反激之用，概置不录，
专事坦夷，以适时宜。其间琐琐，固无足论。即濒湖之博洽今古者，尚尔舍本逐末，仅以《
本经》主治冠列诸首，以为存羊之意。惟仲淳缪子开凿经义，迥出诸方，而于委婉难明处，
则旁引《别录》等说，疏作经言，朱紫之混，能无戾乎？昔三余乔子有《本经注疏》一册，
三十五年前于念莪先生斋头曾一寓目，惜乎，未经刊布，不可复睹。因不自揣，聊陈鄙见，
略疏《本经》之大义，并系诸家治法，庶使学人左右逢原，不逾炎黄绳墨，足以为上工也。
上工十全六，不能尽起白骨而生之。吾愿天下医师慎勿妄恃己长，以希苟得之利，天下苍生
确遵有病不治，常得中医之戒，跳出时师圈缋，何绳墨之可限哉。
康熙乙亥春王石顽张璐书于隽永堂
时年七十有九
医生拥有《神农本草经》，就像工匠拥有墨线一样。有了墨线之后才能确立规矩，有了规矩之后才能懂得变通。变通产生于智慧与技巧，但必须基于墨线的准则。
追溯炎帝所著的《本经》，它是墨线的创始之作；《大观本草》和《证类本草》，是规矩形成的准则；李时珍的《本草纲目》，是在准则基础上的集大成者，但未能达到完全变通的境界。这就好比高明的工匠能教给人规矩，但不能教给人智慧与技巧。能够以智慧技巧与人相通，从而通达变通之道的是黄帝《灵枢》和《素问》中的文章。能够运用炎黄（炎帝、黄帝）之道随机应变，不被墨线所拘束的人，只有汉代的长沙太守张仲景一人罢了。张仲景凭借天赋之才，一脉相承炎黄之道，信手拈来皆是合乎法度的准则。未曾听说在炎黄之道之外还有其他的墨线。
我曾思考医学界的学术传承，并非没有历代名人，但寻求根本、澄清源头，尊崇《本经》主治原则的，除了《玉函经》和《金匮要略》之外，我未曾听闻。张仲景之后，唐代隐士孙思邈的《千金方》独自得其精髓，其处方用药的峻烈程度，甚至超过张仲景，后世难以效法宗奉。因此，编纂本草著作的人，都将上古时期逆顺反激等非常规用法一概不予收录，专门从事平缓稳妥之法，以适应当时的时宜。其中琐碎的内容，本来就不值得讨论。即使是像李时珍那样博古通今的人，也还是舍弃根本追求末节，仅仅把《本经》的主治内容列在诸药之首，以此作为保存经典原意的意图。只有缪希雍（字仲淳）挖掘阐发经典义理，远超其他医家，但在委婉难懂之处，则广泛引用《名医别录》等说法，疏解为经文之言，这种朱紫混淆的做法，难道不违背了正道吗？
过去三余乔子曾有一册《本经注疏》，三十五年前我在念莪先生的书斋中曾偶然读过，可惜未经刊印出版，如今已无法再见到。因此我不自量力，姑且陈述我的浅见，简要疏解《本经》的大义，并附上各家治疗方法，希望使学习者能够左右逢源，不超出炎黄之道的规范，足以成为上等的医生。上等医生治病十次能治愈六次，不能起死回生。我希望天下的医师千万不要妄自尊大，依靠自己的长处去谋求苟且的利益，天下百姓确实应遵循“有病不治，常得中医”的告诫，跳出当时庸医的圈套，那还有什么墨线可以限制呢？
康熙乙亥年（1695年）春季，王石顽张璐书写于隽永堂。
当时年龄七十九岁。
The physician's possession of the *Shennong Bencao Jing* (Divine Farmer's Materia Medica) is akin to a carpenter's possession of a plumb line. With a plumb line, rules and compasses are established; with rules and compasses, flexibility and adaptation become possible. Flexibility arises from wisdom and skill, yet it must still be grounded in the standard of the plumb line.
Tracing back, Yan Di's (Emperor Yan) *Bencao Jing* represents the creation of the plumb line; the *Daguan Bencao* and *Zhenglei Bencao* represent the formation of rules and compasses; Li Shizhen's *Bencao Gangmu* (Compendium of Materia Medica) is a culmination within these standards but has not reached the level of complete adaptability. It is like a master craftsman who can teach others the rules and compasses but cannot impart wisdom and skill. Those who can impart wisdom and skill to achieve the path of adaptability are found in the texts of Huang Di's (Yellow Emperor) *Ling Shu* (Spiritual Pivot) and *Su Wen* (Basic Questions). Among those who could apply the Dao of Yan and Huang flexibly according to circumstances, unconstrained by rigid standards, there was only one person in the Han Dynasty: Zhang Zhongjing, the Prefect of Changsha. Zhang Zhongjing, endowed with heaven-given ability, inherited the Dao of Yan and Huang in an unbroken lineage; whatever he did naturally conformed to the standards. It has never been heard that there exists another plumb line outside the Dao of Yan and Huang.
I have often pondered the academic traditions in the medical field. Although there have been notable figures in every generation, those who seek the root, clarify the source, and revere the therapeutic principles of the *Bencao Jing*, other than the *Yuhan Jing* (Jade Box Classic) and *Jingui Yaolue* (Essential Prescriptions of the Golden Cabinet), I have not encountered. After Zhang Zhongjing, Sun Simiao, a Tang Dynasty recluse, uniquely grasped the essence in his *Qianjin Fang* (Prescriptions Worth a Thousand Gold). His prescriptions were sometimes more potent than those of Zhang Zhongjing, making them difficult for later generations to emulate or revere. Consequently, compilers of materia medica generally omitted the unconventional uses of reversal and stimulation found in ancient texts, focusing instead on mild and safe methods to suit contemporary needs. The trivial details therein are hardly worth discussing. Even Li Shizhen, who was erudite across past and present, still abandoned the root for the branches, merely listing the indications of the *Bencao Jing* at the beginning of each herb entry as a gesture to preserve the original intent. Only Miao Xichun (courtesy name Zhongchun) excavated and elucidated the classic meanings, surpassing other physicians. However, in places where the meaning was subtle and hard to explain, he extensively cited the *Bielu* (Supplementary Records) and other texts, interpreting them as canonical statements. Could such confusion of red and purple (right and wrong) fail to deviate from the truth?
In the past, Qiao Zizi of Sanyu authored a volume titled *Bencao Jingshu*. Thirty-five years ago, I happened to read it once in Mr. Nian'e's study. Alas, it was never published, so it can no longer be seen. Therefore, presuming upon my own limited abilities, I briefly state my humble views, outlining the major principles of the *Bencao Jing* and appending the therapeutic methods of various schools. This may enable students to find resources everywhere, staying within the norms of the Yan-Huang tradition, thus becoming superior physicians. A superior physician cures six out of ten cases and cannot raise the dead back to life. I wish that all physicians in the world would carefully avoid relying arrogantly on their strengths to seek opportunistic gains. The common people should indeed heed the warning: "If one does not treat illness improperly, one often receives the benefit of average medicine." By stepping out of the circle of contemporary mediocre practitioners, what plumb line could possibly constrain them?
Written by Zhang Lu, styled Wangshiweng, at Junyong Hall in the spring of the Yihai year of the Kangxi reign.
At the age of seventy-nine.