齐一变至于鲁。鲁一变至于道。道之兴废。靡不由风俗之变通。非达道人。不能达权通变。
以挽风俗之 弊也。今夫医道之变至再至三。岂特一而已哉。余生万历丁巳。于时风俗虽漓。古
道未泯。业是道者。各擅专科。未尝混厕而治也。甲申世变。黎庶奔亡。流离困苦中病不择医。
医随应请。道之一变。自此而始。当是时也。HT HT 火孑遗。托迹灵威丈人之故墟。赖有医药种树之
书消磨岁月。因循、十有余载。身同匏系。聊以着书自娱。岁己亥赋归故园。箧中辑得方书一通。
因名医归。大都吻合准绳。其间汇集往古传习诸篇。多有不能畅发其义者。次第以近代名言易之。
草创甫成。同人速予授梓。自揣多所未惬。难以示人。仅以伤寒缵绪二论先行问世。颇蒙宇内颔
之。壬寅已来。儒林上达。每多降志于医。医林好尚之士。日渐声气交通。便得名噪一时。于是医
风大振。比户皆医。此道之再变也。嗟予固陋。不能与世推移。应机接物而外。时与先圣晤对一
堂。无异手提面命。递年已来。颖秃半床。稿凡十易。惜乎数奇不偶。曩因趋赴孝伯耿公之招。
携至 川公署。失去目科一门。先是内侄顾惠吉。持去痘疹一册。久假不归。竟成乌有。知机不
偶。已将残编置之高阁。无复行世之心矣。近闻悬壶之士。与垂帘之侣。互参恒德之术。圣门之
教无违。炎黄之德不显。道之三变。匪特自今。吾于志学之年。留心是道。迄今桑榆入望。历世
颇多。每思物壮则老。时盛必衰。欲挽风俗之 弊。宁辞笔削之罪知。因是仍将宿昔所述之言。
从头检点。爰命倬儿补辑目科治例。柔儿参入痘疹心传。足成全编。易以通名。标诸签额。书未
竟。适逢客至。随手开函而语予曰。在昔韩氏医通名世已久。今子亦以是名。得无名实
相混之虑乎。予谓不然。吾闻元氏集名长庆。白氏之集亦名长庆。二集并驱。后世未尝因名混实。
奚必拘拘于是耶。客莞然而退。遂以医通定名。迨夫三变之术。法外之法。非可言语形容也。
康熙乙亥季夏石顽张璐时年七十有九
齐国的风俗变革一次可以达到鲁国的水平，鲁国的风俗再变革一次就可以达到先王之道了。道的兴盛与衰败，没有不是由风俗的变迁所决定的。如果不是通达事理的人，就不能权衡变通，以挽救风俗的弊端。
如今医道的变迁已经两次、三次，哪里只是一次而已呢？我出生于万历丁巳年（1617年），那时虽然世风日下，但古人的正道尚未泯灭。从事这个行业的人，各自擅长专科，未曾混杂在一起行医。甲申年（1644年）发生世事巨变，百姓流亡逃散，在流离失所、困苦不堪中生病时不再选择医生，医生也随着情况随时被请去诊治，这是医道的第一次变迁，从此开始。
当时战火余烬未熄，我寄居在灵威丈人（指代隐居或修道之地）的故墟之中，依靠医药种植方面的书籍来消磨岁月，因循度日十多年，身体如同被匏瓜系住一般不得自由，姑且通过著书来自娱自乐。到了己亥年（1659年）我回到故乡，从箱箧中整理出一部方书。因为名医归聚于此，书中的内容大多符合规范准绳。其中汇集了许多古代流传习用的篇章，有很多未能充分阐发其义理的地方，我便依次用近代的精辟言论替换它们。
初稿刚刚完成，朋友们催促我刻印出版。我自认为还有很多不满意之处，难以展示给人看，仅将《伤寒缵绪》两论先行问世，颇受天下人的认可。自壬寅年（1662年）以来，儒林中的杰出人物多降低身份钻研医学，医界喜好学问的人士也逐渐声气相通，于是名声一时大噪。因此医风大为振兴，家家户户都有医生，这是医道的第二次变迁。
唉，我固然鄙陋，不能随世俗推移，除了应对机缘、接触事物之外，时常与先圣在同一堂屋会晤，无异于亲手教导、当面命令。近年来，笔秃了半床，稿件总共修改了十次。可惜命运乖舛不遇，先前因为赶赴孝伯耿公的邀请，携带至四川公署时，丢失了眼科这一部分。在此之前，内侄顾惠吉借走痘疹一册，久借不还，最终成了无有。知道机遇不凑巧，已将残破的书稿放置在高阁之上，不再有刊行于世的心思了。
最近听说悬壶济世的医生与垂帘诊脉的女医者，互相参悟恒德之术，这与圣门的教诲没有违背，炎黄之德也不显缺失。医道的第三次变迁，不仅仅是从现在开始。我从立志求学的年纪起就留心这个领域，直到如今桑榆晚景已现，经历世事颇多。常常想到事物强盛就会衰老，时势繁盛必然衰退。想要挽回风俗的弊端，岂能推辞删改著作的罪责呢？因此仍将往日所述之言，从头仔细检查。于是命令儿子张倬补充辑录眼科治例，儿子张柔参入痘疹心传，足以成全全书。更改书名以“通”为名，标注在签额上。
书尚未完成，恰好遇到客人来访，随手打开书函对我说：“从前韩氏的《医通》闻名已久，现在您也用这个名字命名，难道没有名实相混的顾虑吗？”我说不是这样。我听说元稹的文集名为《长庆》，白居易的文集也叫《长庆》，两部文集并驾齐驱，后世从未因为名字相同而混淆其实质。何必拘泥于此呢？客人微笑着退下。于是确定书名为《医通》。至于这三次变迁中的医术，法外之法，是不可用言语形容的。
康熙乙亥年（1719年）夏季最后一个月，石顽张璐，时年七十九岁。
From the transformation of Qi, one can reach the standard of Lu; from the transformation of Lu, one can reach the Dao (the Way). The rise and fall of the Dao are determined by nothing other than the changes in customs and morals. Only a person who is thoroughly versed in principles can weigh circumstances and adapt to changes, thereby remedying the defects of social customs.
As for the medical profession, its transformations have occurred twice and thrice; how could it be just once? I was born in the Ding-Si year of the Wanli era (1617). At that time, although worldly morals were declining, the ancient righteous path had not yet vanished. Practitioners of this art each specialized in their own fields and did not mix indiscriminately in practice. In the Jia-Shen year (1644), world events changed drastically, and the common people fled and scattered. Amidst displacement and hardship, patients sought medical help without choosing their doctors, and physicians attended cases as they arose. This marked the first transformation of the medical profession, beginning from this point.
At that time, remnants of war fires still lingered. I took refuge in the ruins associated with Lingwei Zhangren (a metaphorical reference to a hermitage or place of cultivation), passing the years relying on books regarding medicine and horticulture. For over ten years, I drifted along, my body bound like a gourd, finding only solace in writing books for self-entertainment. In the Ji-Hai year (1659), I returned to my hometown. From my chest, I compiled a collection of medical formulas. Since renowned physicians gathered there, the content largely adhered to established standards. Among them were various chapters passed down from antiquity, many of which failed to fully elucidate their meanings. I sequentially replaced these with refined expressions from later generations.
Once the draft was completed, colleagues urged me to have it printed. Feeling that much remained unsatisfactory and unfit for public display, I initially published only two treatises, *Zanshu of Shanghan* (Continuation of Treatise on Cold Damage), which received considerable approval from scholars across the realm. Since the Ren-Yin year (1662), eminent figures from the Confucian scholarly community began to lower themselves to study medicine. Enthusiasts within the medical community gradually established connections and mutual support, leading to widespread fame. Consequently, the medical ethos flourished, and nearly every household had a physician. This constituted the second transformation of the medical profession.
Alas, I am inherently narrow-minded and cannot shift with the times. Aside from responding to opportunities and interacting with things, I often felt as if I were conversing with the Sages in the same hall, receiving their direct guidance. Over the past years, my brushes have worn down half a bed, and the manuscript has undergone ten revisions. Unfortunately, my fate was ill-starred. Previously, while traveling to Sichuan at the invitation of Lord Geng Xiaobo, I lost the section on ophthalmology. Earlier, my nephew-in-law Gu Huiji had borrowed a volume on smallpox and measles, never returning it, so it became lost. Realizing that opportunities were not favorable, I placed the fragmented manuscripts on a high shelf, losing any desire to publish them.
Recently, I have heard that practitioners hanging the pot (physicians) and women practicing medicine behind curtains mutually refine the art of constant virtue. This aligns with the teachings of the Sage’s school and does not diminish the virtue of Yan and Huang. The third transformation of the medical profession is not merely starting now. Since my youth, when I set my mind to learning, I have focused on this art. Now, as I look towards my twilight years, having witnessed many historical changes, I often reflect that things grow old when they are strong, and prosperity inevitably declines. To remedy the defects of customs, how could I shirk the responsibility of editing and compiling? Therefore, I reviewed my previously written words from the beginning. I instructed my son Zhuo to supplement the section on ophthalmology, and my son Rou to incorporate the transmission of knowledge on smallpox and measles, thus completing the entire work. I changed the title to include "Tong" (Comprehensive/Unimpeded) and marked it on the label.
Before the book was finished, a guest happened to visit. Opening the box casually, he said to me, "Han Shi's *Yitong* (Medical Compendium) has been famous for a long time. Now you also name your work with this title. Do you not worry about confusion between name and substance?" I replied, "Not so. I have heard that Yuan Zhen's collected works are named *Changqing*, and Bai Juyi's collected works are also named *Changqing*. The two collections stand side by side, and later generations have never confused their substances because of their names. Why must one be so拘拘 (pedantic/constrained) about this?" The guest smiled and withdrew. Thus, the title *Yitong* was finalized. As for the techniques involved in these three transformations, and the methods beyond conventional rules, these cannot be described by words.
In the last month of summer in the Yi-Hai year of the Kangxi era (1719), Shiwang Zhang Lu, aged seventy-nine.