医家惟小儿科为尤难。盖自其能言而被病者，犹可以问而知之，而其未能言者，不可以
问而知也。《史》言扁鹊入咸阳，为小儿医，然鹊之书多不传其言。有曰∶望而知之谓之神，
闻而知之谓之圣，鹊之术固不在于书欤。信斯言也！惟鹊为可也。夫医不可以无书也，太仓
公乃亦以医者意耳，不肯为书，使仓公者常有于世焉，虽无书可也，如仓公之不常有。何哉？
且吾闻学医者，与学儒无异。儒者求圣贤之心法，以有圣贤之书存焉耳。医无其书，则轩岐
之心法泯焉而不传久矣。又何由而学之？故医书之浩衍，与儒书相埒，殆又过之。然板行于
天下，人得而有之者，往往大方脉之书为多，彼为小儿者，每以专科自名，或私得一方，即
祖父子孙相传，世享其利，他人万金罔顾授也。其肯与天下后世公共之哉？育溪曾君，用儒
攻医，得戴刘二家之传，自少至老，凡活人之幼者，枚数不知几何人。在证处方，皆超然众
医之表，乃以得之师传者，广粹精核，为活幼心书一编。既成不以私其家，将以公之天下后
世，使为其术者，无学医废人之患。凡人之幼，皆有成人之望焉，浓哉育溪之用心也，人孰
无此心哉？皆能以育溪之心为心则善矣。虽然，书本陈言，心须活法，或徒泥其书而不善用，
譬之兵家，不知合变，胶柱而调瑟焉，吾未见其可也。昔临安李立之者，以小儿科擅名一时。
有婴儿忽病喑，求治之，立之令人乘高扑之地下，以一衾盛之，儿不觉大惊，遂发声能言。问
之。曰∶此乳搐心也，非药所能疗。此活法之说也，因附着之。
泰定丁卯闰九月朔中议大夫前同知海北海南道宣慰使司事副都元帅和尼赤序
医家中，唯独小儿科最为艰难。大概是因为那些能够说话并患病的孩子，还可以询问病情来了解病因；而那些尚不能说话的孩子，就无法通过询问来知晓病情了。《史记》记载扁鹊进入咸阳，成为专门治疗儿童的医生，然而扁鹊的著作大多没有流传下来，他的言论也是如此。有人说：“望诊就能知道病情称为神，闻诊就能知道病情称为圣”，扁鹊的医术本来就不在于书籍之中吧？如果相信这种说法，只有扁鹊那样的人可以做到了。但是医学是不能没有书籍的，太仓公（淳于意）也认为行医靠的是心意领悟，不肯著书立说，假如像太仓公这样的人才常存在于世间，即使没有书籍也可以；但像太仓公这样的人并不常见。为什么呢？况且我听说学习医学，与学习儒家经典没有不同。儒者探求圣贤的心法，是因为有圣贤的书籍留存于世罢了。如果医学没有书籍，那么黄帝、岐伯的心法就会湮灭而不传很久了。又从哪里去学习呢？所以医书的繁多浩大，与儒家经典相当，甚至超过它们。然而刊印流行于天下的书籍中，人们能够得到的，往往是大病科（成人内科）的书籍较多；那些从事儿科的医生，常常以专科自居，或者私自得到一方，就作为祖父子孙世代相传，世代享受其利，别人即使用万金也不肯传授。他们肯将医术公开给天下后世吗？育溪的曾君，用儒家的方法攻习医学，得到了戴、刘两家的真传，从少年到老年，凡是他救活的儿童，数都数不清有多少人了。他在辨证处方时，都超然出众医之上，于是将师传所得，广泛搜集、精炼核实，编成《活幼心书》一卷。书成之后，他不将其据为己有，而是打算将它公之于天下后世，使从事此术的人，没有因学医而耽误救治他人的祸患。凡是年幼的儿童，都有长成成年人的希望啊，育溪的用心真是深厚啊，人谁没有这种心呢？都能以育溪的心为心就好了。虽然如此，书本上是陈旧的言论，心中必须有灵活的方法，如果仅仅拘泥于书本而不能善于运用，就像兵家不知道随机应变，胶柱鼓瑟一样，我看是不行的。从前临安有个叫李立之的人，凭借小儿科在当时享有盛名。有一个婴儿突然失音，求他治疗，李立之让人把婴儿抱到高处置于地下，用一床被子裹住他，婴儿不觉受到极大惊吓，于是发出声音能说话了。问他原因，他说：“这是乳搐心（因受惊导致的心气郁闭），不是药物所能治疗的。”这就是灵活运用的说法，因此附记于此。
泰定丁卯年闰九月初一，中议大夫、前同知海北海南道宣慰使司事、副都元帅和尼赤作序。
Among medical practitioners, pediatrics is particularly difficult. This is because for those who can speak and are ill, one can inquire to understand the condition; but for those who cannot yet speak, inquiry alone cannot reveal the illness. The *Records of the Grand Historian* states that Bian Que entered Xiangyang and practiced as a pediatrician; however, his writings and words were largely not transmitted. It is said: "To know through observation is called divine; to know through listening and smelling is called sage." Was Bian Que's art indeed not dependent on books? If this statement is true, only someone like Bian Que could manage it. Yet medicine cannot exist without books. Taicang Gong (Chunyu Yi) also believed that medical practice relies on mental comprehension and was unwilling to write books. Had there always been people like Taicang Gong in the world, books might have been unnecessary; but such individuals are rare. Why? Moreover, I have heard that studying medicine is no different from studying Confucianism. Confucians seek the core principles of sages because the books of sages exist. If medicine had no books, the core principles of Huangdi (Yellow Emperor) and Qibo would have long been lost and untransmitted. How then could one learn? Therefore, the vast number of medical texts rivals or even exceeds that of Confucian classics. However, among the printed works available to the public, those on adult internal medicine (Da Fang Mai) are predominant. Pediatric specialists often keep their expertise secret, passing prescriptions down father to son, enjoying benefits for generations, refusing to teach others even for ten thousand gold pieces. Would they willingly share their knowledge with the world and future generations? Mr. Zeng of Yuxi, applying Confucian scholarship to medicine, inherited the traditions of Dai and Liu. From youth to old age, the number of children he saved is countless. In diagnosing and prescribing, he consistently surpassed other physicians. He thus collected, refined, and verified what he learned from his teachers, compiling it into a volume titled *Huoyou Xinshu* (New Book for Saving Children). Upon completion, he did not keep it private but intended to make it public to the world and posterity, ensuring that practitioners would not suffer the harm of being unable to save lives due to lack of learning. Every young child holds the hope of becoming an adult; how profound is Mr. Zeng's dedication! Who does not possess such a heart? It would be excellent if everyone could adopt Mr. Zeng's mindset. Nevertheless, while books contain established doctrines, the mind must employ flexible methods. If one merely adheres rigidly to the text without skillful application, it is like a military strategist who fails to adapt, akin to gluing the bridges of a zither before tuning it. I do not see how this would work. In the past, Li Lizhi of Lin'an gained fame for his pediatric skills. An infant suddenly lost its voice and sought treatment. Li Lizhi ordered someone to lift the child high and drop them to the ground, wrapping them in a blanket. The infant, greatly startled, suddenly cried out and could speak again. When asked, he replied: "This is Ru Chu Xin (infant convulsion affecting the heart), which cannot be cured by medicine." This illustrates the principle of flexible application, so I have appended this account.
Preface by He Nichi, Zhongyi Dafu (Counselor of Moderate Rank), Former Tongzhi (Joint Director) of the Xuanweishi Office of Haibei-Hainan Circuit, and Vice Marshal, on the first day of the intercalary ninth month of the Dingmao year of Taiding.