闻之先儒曰∶天向一中分造化，人于心上起经论。大哉心乎！其万事之机括乎，前乎千
百世而上，为天地立心，生民立命者，此心也。后乎千百世而下，为往圣继绝学，来者续师
传，亦此心也，是心也，以之活幼，即有恻隐之真，所谓乍见孺子将入于井，皆有怵惕恻隐
者，无非自此心中来。宋翰林侍御世医戴克臣者（徽宗朝，名尧道，）活幼宗师也，取信当时，有声
朝野，心以传心，得其妙者，惟 西高原刘茂先（名祀自号固穷山叟。）茂先之心，其五世孙字直甫者
（名思道），又深得之。推其所得，随施辄效，亦可以见其用心矣。然昔贤之学，固以心而传，而
昔贤之心，非书又无以衍其传。况自开庆以来，其书散漫，戴刘二公之心传，几不复见。予
生二公之后，而无默契乎二公之心，早岁师事直甫，于兹有年，面命心传，领会多矣。但念
一宗医书，方论待决，岁月浸远，卷帙不齐，设有危难，未易检阅。吁！得其心者，敢不究
其心哉。明窗昼熏，短檠夜雨，因就其遗书而精加编次，繁者删之，缺者补之，书非可用不
敢录，方非已效弗敢收。脱亡遗漏，存十一于千百，上探三皇前哲之遗言，下探克臣茂先之
用心，实则吾心固有之理，旁求当代明医之论，亦姑为活幼之一助云耳。遂名其书曰活幼心
书。书成，客或难予曰∶医者意也。但观形切脉，以意逆志，是为得之，何必一切求诸书，而
且以心书名之哉。予曰∶不然。予非有心于着述，而求异于人也。不过推展刘氏数传之贞心。
以求契夫戴氏之初心耳。朱文公有言，意者，心之所发也。书之所述，岂非心之流行发见者
乎！客唯而退，于是乎书。
至元甲午菊节衡阳后学曾世荣德显识
听先前的儒者说：“天道在‘一’中分化出造化，人道在‘心’上建立起经纶。”心啊，真是伟大！它大概是万事万物的枢纽吧。在千百世之前，为天地确立本心，为百姓确立命运，靠的是这颗心。在千百世之后，为往圣继承断绝的学问，让后来者延续师承传授，也是靠这颗心。这颗心，用来救治幼儿，便会有真正的恻隐之心，正如所谓“突然看见一个小孩快要掉进井里”，人们都会产生惊惧和同情之情，这些情感无非都从这颗心中产生。
宋代翰林侍御、世代行医的戴克臣先生（宋徽宗朝时名叫尧道），是救治幼儿的宗师，取信于当时，在朝廷和民间都有声望。心以传心，领悟其奥妙的，只有西高原的刘茂先先生（名叫祀，自号固穷山叟）。刘茂先的心法，他的五世孙字直甫的人（名叫思道），又深得其中精髓。推广他所获得的经验，随即施用随即见效，也可以看出他的用心了。然而，从前贤人的学问，固然以心相传，但从前贤人的心法，如果不通过书籍，就无法流传下去。况且自从开庆年间以来，那些书籍散失漫漶，戴公和刘公的心法传承，几乎不再可见。我生在二公之后，虽然没有与他们的心法默契相通，但早年拜直甫先生为师，到现在已有多年，当面受教，心法相传，领会了很多。只是想到这一脉的医书，方剂和论述等待决断整理，岁月渐渐久远，卷册不全，假设有危急困难的情况，不容易查阅。唉！得到了他们心法的人，怎敢不探究他们的心意呢？于是我在明亮的窗前白天熏香，在昏暗的油灯下夜晚听雨，就着他们的遗书精心加以编排整理，繁杂的删减它，缺失的补充它，书不是有用的不敢收录，方子不是自己验证有效的不敢收集。脱漏遗漏的，只存留千百分之一，向上探求三皇以前哲人的遗言，向下探求克臣、茂先二人的用心，这实际上是我心中固有的道理，旁求当代名医的论述，也只是姑且作为救治幼儿的一个帮助罢了。于是给这本书命名为《活幼心书》。
书编成后，有客人责问我道：“医者，意也。只要观察形态、切按脉搏，用心意去推测病情，这就足够了，何必一切都求助于书籍，而且还要用‘心’来命名这本书呢？”我说：“不对。我并不是有心于著述，以求与众不同于人。不过是推展刘氏几代传承的纯正心意，以求契合戴氏最初的初心罢了。朱熹文公有句话说：‘意，是心的发动。’书中所述的，难道不是心的流行和显现吗！”客人点头退下，于是写下了这篇序。
至元甲午年菊花节，衡阳后学曾世荣德显识记。
I have heard from former Confucian scholars say: "Heaven and Earth divide creation within the 'One'; Humanity establishes its principles upon the 'Mind'." Great is the Mind! It is likely the pivot of all affairs. Before a thousand or hundred generations, establishing the mind for Heaven and Earth, and securing life for the people, was this Mind. After a thousand or hundred generations, continuing the lost learning of past sages, and allowing successors to inherit the teacher's transmission, was also this Mind. This Mind, when applied to treating children, manifests as true compassion. As it is said, "Suddenly seeing a toddler about to fall into a well," everyone experiences alarm and compassion; these emotions all originate from this Mind.
Dai Kechen (courtesy name Yaodao) of the Song Dynasty, an Imperial Hanlin Scholar and Physician by Hereditary Office, was a grandmaster in treating children. He gained trust in his time and had a reputation in both the court and the folk. Passing the Mind through the Mind, only Liu Maoxian of Xigao Yuan (personal name Si, pseudonym Guchong Shansou) grasped its subtleties. The fifth-generation grandson of Liu Maoxian, with the courtesy name Zhifu (personal name Sidao), deeply inherited this essence. Extending what he had acquired, he applied it and achieved immediate effects, which could reveal his dedication. However, the learning of former sages was indeed transmitted via the Mind, but without books, the Mind of former sages could not be propagated. Moreover, since the Kaiqing era, their books have become scattered and disordered, and the mind-to-mind transmission of Dai and Liu has almost disappeared.
Born after these two masters, I did not share a tacit understanding of their Minds. In my early years, I served as a disciple to Zhifu, and for many years now, receiving face-to-face instruction and mind-to-mind transmission, I have comprehended much. Yet, considering that the medical texts of this lineage require resolution regarding prescriptions and theories, and as years pass, the volumes are incomplete, making them difficult to consult in emergencies. Alas! Those who have obtained the Mind, how dare they not investigate the Mind? Under a bright window with incense burning during the day, and by a short lamp listening to night rain, I compiled and edited their remaining writings. I deleted the redundant, supplemented the missing. If a book was not useful, I dared not record it; if a prescription was not effective, I dared not collect it. What remained was but one part in a thousand, seeking upwards the legacy of the sages before the Three Sovereigns, and downwards the dedication of Kechen and Maoxian. This is essentially the inherent principle within my own Mind, alongside seeking the discussions of contemporary renowned physicians, merely as an aid for treating children. Thus, I named this book *Huoyou Xinshu* (Heart Book for Saving Children).
When the book was completed, a guest challenged me saying: "Medicine is intention (Yi). One need only observe the form and feel the pulse, using intention to infer the will/pathology, and one has attained it. Why seek everything in books, and why name the book with 'Mind'?" I replied: "Not so. I do not intend to write for the sake of being different from others. I merely extend the pure heart transmitted through several generations of the Liu family, seeking to align with the original heart of the Dai family. Zhu Xi stated: 'Intention is the emission of the Mind.' Is what is described in the book not the flow and manifestation of the Mind?" The guest nodded and withdrew. Thus, this preface was written.
Recorded by Zeng Shirong, courtesy name Dexian, a junior scholar from Hengyang, on the Chrysanthemum Festival of the Jiawu year of the Zhiyuan era.