对于经典，熟读强识是非常重要的。古人说：读书百遍，其义自现。这个口诀尤其适用于经典的学习。学后世 思考中医的书，我们不用读百遍，有时一遍就行了，而对经典，非读百遍不行，尤其是像《伤寒论》这样的典籍。有些人读经一二次就想过关。一二次没有感悟，就以为经典没什么，丢在一旁了。这哪是读经典呢？这是把茶当饮料喝了。你把巴赫的曲子当成了“冬天里的一把火”，你怎么会感受出味道呢？有关读经，我以为曾国藩的经验很值得借鉴，他在道光二十三年给其诸弟的一封信中有下面这样一段记述：“穷经必专一经，不可泛骛。读经以研寻义理为本，考据名物为末。读经有一耐字诀：一句不通，不看下句；今日不通，明日再读；今年不精，明年再读，此所谓耐也。”曾国藩的这个“耐”字诀，可谓深得读经三昧。当然，对于曾氏的这个诀我们也可以灵活地看，不一定这句不通，就不读下句。但是，今日不通，明日再读；今年不精，明年再读，这是一定要做的。总之，读经不是三年、二年的事，更不是三月、二月、一个学期的事，读经是一辈子的事。经要放在案头，更要常置心头。经典是一辈子的必修课，你要想真正学好中医，学好经典，就必须做这样的打算。
（3）基本条件
学好经典需要注意的另外一个问题，就是要具备一个基本条件，或者说一个基本的素质，这就是信受奉行。现在很多人学经典是带着一种批评的眼光来学，觉得经典这也不科学，那也不科学，你比经典都高明了，那你还学什么经典呢？你以一种抵触的情绪，认为经典过时了，那你怎么学得进经典？所以，学经典这个态度很重要，你必须完全地相信它，接受它，然后再思考怎么按照经典的思想去奉行。只有这样，经典才学得进，只有这样，你才会有收获。经典经过了那么长时间的考验，那么多人依靠经典成了名医，你有什么担心呢？所以，对于经典完全地可以信受奉行。这里为什么要提出这个条件和素质呢？因为它太重要了。不具备这个条件，经典的学习整个就成了障碍。记得在读《本草纲目》的时候，谈到白术这一条时，李时珍引了张锐《鸡峰备急方》的一则案例：“察见牙齿日长，渐至难食，名曰髓溢病。用白术煎汤，漱服即愈。”大家看到这个案例，你的第一感觉是什么呢？我想很多人会不相信。牙齿长到一定程度就定型了，怎么会越长越长，以致进食都困难呢？这太离谱了。即便有这个髓溢病，牙齿那么坚硬的东西，怎么用白术漱漱口就能缩回去呢？简直太不科学了。但，我不这么想，我首先是相信它，然后，再来思考它的道理。首先，这个病名很有意思。牙齿为骨之余，由肾所主。肾主骨生髓，骨与髓乃是异名同类的东西。牙齿日长，就好像是髓满了在往外溢一样，所以，叫做髓溢病。现在要考虑的是这个牙齿为什么会日渐长长？髓为什么会往外溢？这一定是约束骨、髓的这个系统出了问题。骨、髓由肾所主，肾为水藏，故骨髓亦属水类，明白了这层关系，就知道对骨、髓的约束功能是由土系统来完成的，这亦是前面所讲的土克水。现在土系统出了问题，土虚了，当然就会发生水溢，当然就会发生髓溢。髓溢了，牙齿自然会日渐变长。这个道理明白了，用白术来补土制水，控制髓溢，就是十分简单的事了。这是我对髓溢病及其治疗的思考过程。1991年接治一位跟骨骨刺的患者，患者的双跟都有骨刺，疼痛厉害，以致足跟不敢落地，要踮起脚来走路，所以，生活感到很困难。我按常规的思路，用了补肾的方法，也用了活血、除痛、蠲痹的其他方法，但，都没有获得明显的疗效。正在我感到进退两难的时候，突然想到了上面的这个案例。骨刺病也叫骨质增生，是由于骨钙流失到骨面，形成思考中医骨性赘生物所致。骨钙流失形成骨性赘生物，这与髓溢有什么差别呢？应该没有差别。于是我如法炮制，用白术煎汤，让患者浸泡足跟，每日二三次，每次 20 分钟。出乎意料，不数日，痛即大减，足跟能够落地，坚持近月，病即痊愈。上面这个例子给我的感受很深，什么感受呢？就是对这个“信受奉行”的感受。对这件事我首先是相信了，相信了才有可能去进行上面的思考。如果对这件事根本不相信，那怎么会有以后的思考？没有这些思考，就不会想到要用白术来治疗跟骨骨刺。所以，相信是第一，只有这一步做好了，才有可能为今后的研究带来机会。如果首先就不信受，那一切就被你拒绝了，一切的机会就没有了。大家想一想是不是这么回事。因此，这一节里讲的这个条件，也是学习中医必须具备的一个条件。以上这一章，我们从宏观的方面，理性的方面，和从某些感受上谈了中医学习和研究的一些基本问题，只有从思想上把这些问题真正解决了，学习中医才没有障碍，学习经典才没有障碍。
第二章 伤寒之意义
从这一章开始，我们将进入《伤寒杂病论》一些具体问题的讨论，在讨论这些问题前，应该首先弄清楚这部书是一部什么样的书。我想这个问题，我们可以通过论题，通过书名来解决。
1.伤寒的涵义
伤寒，是我们讨论的这部书的核心，有关它的涵义我们应该很清楚。伤寒这个概念，在《素问·热论》里有很明确的定义：“今夫热病者，皆伤寒之类也。”这个定义说明了伤寒的一个非常显著的特征，那就是发热的特征。凡是属于发热性的疾病，或者说凡是具有发热特征的疾病都属于伤寒的范畴。《内经》对伤寒的这个定义，是从最基本的点上去定义的，但是，扩展开来却显得很泛化，不容易把握。为此，到了《难经》的时候，又给它作了一个更具体的定义。《难经·五十八难》云：“伤寒有五，有中风、有伤寒、有湿温、有热病、有温病。”《难经》的这个定义说明了，这个具有发热特征的伤寒常见于五类疾病里，哪五类疾病呢？就是中风、伤寒、湿温、热病、温病。稍稍具有临床经验的人就能感受到，《难经》给伤寒的这个定义确实很具体，临床所见的发热性疾病，大多也就见于这些疾病里面。所以，要研究伤寒，就应该着眼于上述这五类疾病。另外一个需要注意的问题，就是《难经》中谈到两个伤寒，第一个伤寒当然是总义的伤寒，也就是《素问·热论》讲的伤寒，现在的教材又叫它广义伤寒；后一个伤寒是分义的伤寒，又叫狭义伤寒。而我们这个论题上，书名上的伤寒，当然是指第一个意义上的伤寒，这一点不容混淆。这个问题弄清了，我们就知道张仲景并不偏重于谈寒，他也谈湿温、热病、温病。
2.杂病的涵义
伤寒是《伤寒论》或者《伤寒杂病论》这部书的经，但，还有一个纬，这就是杂病。杂病与伤寒相比，它具有什么意义呢？这里先讲一个“文化大革命”的故事。“文化大革命”期间，王洪文当上了党的副主席和军委副主席，但是，大家都知道他一个保卫干事，能有什么特别的才干？有一次当时的副总理邓小平就问王洪文一个问题，说中国到底有多少厕所？让王洪文告诉他。王副主席一听这个问题，当时就愣住了，这个问题我怎么回答？我又没有作过具体调查，毛主席不是说没有调查就没有发言权嘛。看到这个尴尬的局面，总理便在一边解围说，这个问题不用作调查，中国就只有两个厕所，一个男厕所，一个女厕所。这虽然是个玩笑，但是，哲理却很深。联系到伤寒与杂病的概念，如果我们从发热的角度去认识天下所有的疾病，那么，天下的疾病也无外乎两个，一个就是具有发热特征的疾病，一个就是不具备这个特征的疾病。天下的所有疾病中，要么是发热的，要么是不发热的。大家想一想，是不是这么回事？现在，既然发热的疾病让伤寒占去了，那么，不发热的这一类疾病就非杂病莫属了。所以，一个伤寒，一个杂病，已然将天下的疾病占尽了，这就是伤寒与杂病的真实涵义。弄清了上面这个涵义，可以解除我们许多的顾虑。过去我们常会担心，光搞一门伤寒会不会太局限了？担心搞伤寒的只会治外感，不会治内伤；只会治伤寒，不会治温病；或者只会治内科，而不会治其他各科的病。现在我们知道了《伤寒杂病论》是一部什么样的书，知道了它的研究范围。这些问题清楚了，怎么还会有上面的担心？所以，读古书，对书名的理解是很重要的。
3.论的涵义
书名的最后一个字是“论”，大家也别小看了这个字。论在古代是一个很重要的概念，是一个与经相对应的概念。所以，要搞清楚论，必须首先搞清经。“经”是什么？经就是经典。中医有中医的经典，道家有道家的经典，佛家有佛家的经典。这个经典意味着什么呢？它往往代表某一门学问里最权威的东西。经典产生的时代，往往就是这门学问最成熟的年代。这与现代科学的发展模式是不同的。经典的这样一个特性决定了我们要研习这门学问，就得依靠它，这一点我们前面已经讨论过。而经典的另外一个重要特征就是它的作者。经典的作者是很讲究的，像佛家这门学问，只有释迦牟尼所讲述的那些著作能够称经，其他后世的这些著述统统不能称经。儒家的学问也是如此，只有孔子的著述，或孔子删定的诗、书、礼、易能够称经，而后世的那些同样也不能称经。经典作者的这样一个特殊性，使我们发现，他们都是这门学问的开山祖师，只有开山祖师的东西才能称经。开山祖师亦称圣人，像儒家这门学问，只有孔子能称圣人。所以，孔子又被称为“大成至圣先师”，而孔子以后的人统统不够圣人的条件，要称的话，最多勉强称作亚圣、或后圣，亚于圣人、后于圣人。那么，上述的这些圣人，上述的这些经典的作者灭度以后，后人便要对这些经典进行诠释，进行发挥，这些对经典进行诠释和发挥的著述就称之为论。所以说论是与经相对的概念，没有经就没有论。我们从手头的这部书叫论这个名字，就知道它是诠释和发挥经典的著述。上述这个关系清楚后，我们就会发现，在中医界有一个很奇怪的现象，那就是把造论的作者当成了医圣，反而作经的黄帝、岐伯没有称圣。这个现象当然有它的原因，张仲景对中医的贡献太大了，他于危难之中拯救了中医，中医之所以能够延续到今天，张仲景是功不可没的。正是张仲景的这个功绩，他被越称为医圣，他的论亦成了经。但是，作为张仲景自己，他是很谦虚的，他并没有把他的著作叫《伤寒杂病经》，这一点他要比后世的皇甫谧、张介宾高明。有关经论的上述涵义，我们还可以用另外一个关系来说明，那就是“体”与“用”。经为道之体，论为道之用。经以言体，论以明用。没有体不行，如果我们没有强健的身体，那一切的理想都会落空。所以，体是基础，没有它不行。同样，用也很重要，有体而无用，那这个体的意义怎么体现出来？我们光有强健的身体，却不去发挥作用，那么这个身体有什么意义呢？还不是臭皮囊一个！因此，体与用、经与论就是这么一种关系。这样我们就知道了，要学好中医，经必须读，论也必须读，而《伤寒杂病论》呢？它既具有经的一面，又具有论的一面，它既言体，又明用。就是这么一部著作，大家看应不应该读？应不应该把它作为依靠处？
二、认识阴阳 探求至理
上面的论题搞清以后，这就开门见山了。接下来的是要提出三个问题：第一，《素问》里讲：“今夫热病者，皆伤寒之类也。”明明热病就是热病，怎么要把它归到伤寒呢？寒与热是风马牛不相及的事，这是为什么？第二个问题，它与第一个问题也有联系，伤寒就是伤寒，就是一个病嘛，《难经》为什么说“伤寒有五，有中风、有伤寒、有湿温、有热病、有温病。”一个伤寒怎么会包括这么多病，这是一个问题；第三呢？张仲景为什么以伤寒为经？后世的王叔和为什么径直用“伤寒”来作书名？上面这三个问题，是我们在读《伤寒论》前必须搞清的问题，这三个问题弄不清，《伤寒论》你没法子读通。那么，上述的这三个问题，我们如何才能搞清呢？这里可以借用清末四川名医郑钦安的一个窍诀：“学者苟能于阴阳上探求至理，便可入仲景之门也。”因此，学者若欲在仲景这门学问里真正的深入进去，那就必须把阴阳的问题放在首位。
1.认识阴阳
For the classics of Traditional Chinese Medicine (TCM), reading them repeatedly and memorizing them firmly is of great importance. The ancients said, "Read a book a hundred times, and its meaning will reveal itself." This maxim applies particularly to the study of classics. When studying works by later medical scholars, we do not need to read them a hundred times; sometimes once is enough. However, for the classics, reading them a hundred times is indispensable, especially for authoritative texts such as *Shanghan Lun* (Treatise on Cold Pathogenic Diseases). Some people think they can pass after reading the classics only one or two times. If they gain no insight after one or two readings, they may consider the classics insignificant and discard them. Is this how one reads the classics? No, this is like drinking tea as if it were a beverage. If you treat Bach's music as "A Fire in Winter," how can you perceive its true flavor? Regarding the reading of classics, I believe Zeng Guofan's experience is worth emulating. In a letter to his younger brothers in the 23rd year of the Daoguang reign, he recorded: "To thoroughly study the classics, one must focus on one classic at a time and avoid superficial browsing. The primary purpose of reading classics is to explore their principles and meanings, while textual research on names and objects is secondary. There is a key word for reading classics: 'patience.' If one sentence is not understood, do not proceed to the next; if today it is not understood, read it again tomorrow; if it is not mastered this year, master it next year. This is what is meant by patience." Zeng Guofan's emphasis on "patience" truly captures the essence of reading classics. Of course, we can view this principle flexibly; it does not necessarily mean that if one sentence is unclear, one must skip the next. However, "if today it is not understood, read it again tomorrow; if not mastered this year, master it next year"—this is essential. In short, reading classics is not a matter of three or two years, nor of three or two months, or even a single semester; it is a lifelong endeavor. Classics should be kept on the desk and, more importantly, held in the heart. Classics are compulsory courses for life. If you wish to truly master TCM and the classics, you must make such plans.
(3) Basic Conditions
Another issue to note when studying classics is the need to possess a basic condition, or quality, namely "faithful acceptance and practice." Currently, many people study classics with a critical eye, thinking that the classics are unscientific in this regard and unscientific in that. If you are superior to the classics, why study them at all? With a resistant attitude, considering the classics outdated, how can you absorb them? Therefore, the attitude toward studying classics is crucial. You must completely believe in and accept them, and then contemplate how to practice according to their principles. Only in this way can you learn the classics effectively, and only in this way can you gain benefits. The classics have stood the test of time, and many people have become renowned physicians relying on them. What is there to worry about? Thus, one can fully adopt an attitude of faithful acceptance and practice toward the classics. Why emphasize this condition and quality here? Because it is too important. Without this condition, the entire study of classics becomes an obstacle. I recall that when reading *Bencao Gangmu* (Compendium of Materia Medica), under the entry for Atractylodis Rhizoma (Baizhu, 白术), Li Shizhen cited a case from Zhang Rui's *Jifeng Beiji Fang*: "Observing teeth growing longer day by day, gradually making eating difficult, this is named Marrow Overflow Disease. Decocting Atractylodis Rhizoma and using the decoction to rinse the mouth and swallow it leads to immediate cure." What is your first impression upon seeing this case? I imagine many would disbelieve it. Teeth reach a certain size and then stabilize; how can they continue to grow until eating becomes difficult? This seems absurd. Even if Marrow Overflow Disease exists, how can rinsing with Atractylodis Rhizoma cause something as hard as teeth to shrink back? It seems utterly unscientific. However, I do not think so. First, I believe it, and then I ponder its rationale. First, the disease name is interesting. Teeth are considered the surplus of bones and are governed by the Kidney. The Kidney governs bones and generates marrow; bones and marrow are different names for similar entities. The daily growth of teeth is akin to marrow overflowing because it is full, hence the name Marrow Overflow Disease. Now, the question is why do the teeth grow longer day by day? Why does the marrow overflow? This must indicate a problem with the system that constrains bones and marrow. Bones and marrow are governed by the Kidney. The Kidney is a Water organ, thus bone and marrow also belong to the Water category. Understanding this relationship reveals that the constraining function over bones and marrow is performed by the Earth system, which corresponds to the previously mentioned Earth overcoming Water. Now, if the Earth system malfunctions and Earth becomes deficient, Water will inevitably overflow, leading to Marrow Overflow. Consequently, the teeth will naturally grow longer day by day. Once this principle is understood, using Atractylodis Rhizoma to tonify Earth and control Water, thereby managing Marrow Overflow, becomes a simple matter. This is my thought process regarding Marrow Overflow Disease and its treatment. In 1991, I treated a patient with calcaneal spurs. The patient had spurs on both heels, causing severe pain such that they could not put their feet flat on the ground and had to walk on tiptoes, making daily life very difficult. Following conventional思路 (approaches), I used methods to tonify the Kidney, as well as other methods to invigorate blood, relieve pain, and dispel bi-syndrome, but none yielded significant effects. Just as I felt stuck between advancing and retreating, I suddenly recalled the aforementioned case. Spur disease, also known as osteohyperplasia, is caused by bone calcium loss to the bone surface, forming bony excrescences. What is the difference between bone calcium loss forming bony excrescences and Marrow Overflow? There should be no difference. Therefore, I applied the same method, decocting Atractylodis Rhizoma and having the patient soak their heels in it two to three times daily for 20 minutes each time. Unexpectedly, within a few days, the pain decreased significantly, and the patient could put their feet flat on the ground. After persisting for nearly a month, the disease was cured. This example left a deep impression on me. What was the impression? It was the realization of "faithful acceptance and practice." For this matter, I first believed it; only by believing could I engage in the above reasoning. If I did not believe it at all, how could there be subsequent reflection? Without these reflections, I would never have thought to use Atractylodis Rhizoma to treat calcaneal spurs. Therefore, belief comes first. Only by completing this step can opportunities for future research arise. If one rejects it initially, all possibilities are denied, and all opportunities are lost. Consider whether this makes sense. Thus, the condition discussed in this section is also a prerequisite for learning TCM. In this chapter, we have discussed some basic issues in TCM learning and research from macroscopic, rational, and experiential perspectives. Only by truly resolving these issues ideologically can one learn TCM without obstacles and study the classics without hindrance.
Chapter 2: The Significance of Shanghan
I. What Does Shanghan Lun Discuss?
Starting from this chapter, we will enter into discussions of specific issues in *Shanghan Zabing Lun* (Treatise on Cold Pathogenic and Miscellaneous Diseases). Before discussing these issues, we should first clarify what kind of book this is. I believe this question can be resolved through the topic and the title.
1. The Meaning of Shanghan
Shanghan is the core of the book we are discussing, and we should clearly understand its meaning. The concept of Shanghan has a clear definition in *Suwen·Relun* (Basic Questions: Treatise on Febrile Diseases): "All febrile diseases nowadays are of the type of Shanghan." This definition highlights a very prominent feature of Shanghan, namely fever. All diseases belonging to febrile conditions, or all diseases characterized by fever, fall within the scope of Shanghan. The definition of Shanghan in *Neijing* (Inner Canon) is based on the most fundamental point, but when expanded, it appears quite generalized and difficult to grasp. Therefore, when *Nanjing* (Classic of Difficult Issues) came along, it provided a more specific definition. *Nanjing·58th Difficulty* states: "Shanghan comprises five types: Wind Strike, Shanghan, Damp-Warmth, Febrile Disease, and Warm Disease." This definition indicates that Shanghan, characterized by fever, commonly appears in five categories of diseases. Which five? They are Wind Strike, Shanghan, Damp-Warmth, Febrile Disease, and Warm Disease. Anyone with slight clinical experience can feel that the definition of Shanghan given in *Nanjing* is indeed specific; most febrile diseases seen in clinical practice fall into these categories. Therefore, to study Shanghan, one should focus on these five types of diseases. Another issue to note is that *Nanjing* mentions two types of Shanghan. The first Shanghan refers to the general meaning of Shanghan, i.e., the Shanghan mentioned in *Suwen·Relun*, which modern textbooks call Broad Sense Shanghan. The second Shanghan refers to the specific meaning, also called Narrow Sense Shanghan. The Shanghan in our topic and title certainly refers to the first meaning, and this must not be confused. Once this issue is clarified, we know that Zhang Zhongjing did not focus solely on cold; he also discussed Damp-Warmth, Febrile Disease, and Warm Disease.
2. The Meaning of Zabing
Shanghan is the "Jing" (Classic/Longitude) of *Shanghan Lun* or *Shanghan Zabing Lun*, but there is also a "Wei" (Supplement/Latitude), which is Zabing. Compared with Shanghan, what significance does Zabing have? Let me first tell a story from the Cultural Revolution. During the Cultural Revolution, Wang Hongwen became Vice Chairman of the Party and the Central Military Commission. However, everyone knew he was merely a security officer; what special talent could he have? Once, then-Vice Premier Deng Xiaoping asked Wang Hongwen a question: How many toilets are there in China? He asked Wang to tell him. Upon hearing this question, Vice Chairman Wang was stunned. How could I answer this? I haven't conducted specific surveys. Didn't Chairman Mao say, "Without investigation, there is no right to speak"? Seeing this awkward situation, the Premier intervened to save the situation, saying, "This question does not require investigation. There are only two types of toilets in China: one for men and one for women." Although this was a joke, the philosophy behind it is profound. Connecting this to the concepts of Shanghan and Zabing, if we understand all diseases in the world from the perspective of fever, then all diseases in the world can be divided into two categories: those with fever characteristics and those without. Among all diseases in the world, either they involve fever or they do not. Think about it, is this not the case? Now, since febrile diseases are covered by Shanghan, the category of non-febrile diseases must belong to Zabing. Therefore, one Shanghan and one Zabing have already encompassed all diseases in the world. This is the true meaning of Shanghan and Zabing. Clarifying the above meanings can alleviate many of our concerns. In the past, we often worried that focusing solely on Shanghan might be too limited. We worried that those studying Shanghan could only treat external contractions, not internal injuries; could only treat Shanghan, not Warm Diseases; or could only treat internal medicine, not diseases of other specialties. Now that we know what kind of book *Shanghan Zabing Lun* is and its scope of research, how could we still have such worries? Therefore, understanding the title is crucial when reading ancient books.
3. The Meaning of Lun
The last character of the title is "Lun" (Treatise/Discourse). Do not underestimate this character. In ancient times, "Lun" was an important concept, corresponding to "Jing." Therefore, to understand "Lun," one must first understand "Jing." What is "Jing"? Jing refers to classics. TCM has its classics, Daoism has its classics, and Buddhism has its classics. What does this classic imply? It often represents the most authoritative work in a particular field. The era in which a classic was produced is often the most mature period of that discipline. This differs from the development model of modern science. Such a characteristic of classics determines that to study this discipline, we must rely on it, as discussed earlier. Another important feature of classics is their authorship. The authors of classics are highly selective. In Buddhism, only the works taught by Shakyamuni can be called Jing; all subsequent writings cannot be called Jing. Confucianism is the same; only the writings of Confucius, or the Poetry, Book, Rites, and Changes edited by Confucius, can be called Jing; subsequent works similarly cannot be called Jing. This特殊性 (specificity) of classic authors leads us to discover that they are all the founding masters of their disciplines. Only the works of founding masters can be called Jing. Founding masters are also called Sages. In Confucianism, only Confucius can be called a Sage. Thus, Confucius is also known as the "Great Accomplished Sage and Former Teacher," and anyone after Confucius does not meet the conditions of a Sage. If they must be titled, they can at best be tentatively called Sub-Sage or Later Sage, inferior to or posterior to the Sage. After these sages and authors of classics passed away, later generations had to interpret and expand upon these classics. These writings that interpret and expand upon classics are called Lun. Therefore, Lun is a concept relative to Jing; without Jing, there is no Lun. From the fact that our current book is named Lun, we know it is a writing that interprets and expands upon classics. Once this relationship is clear, we will find a strange phenomenon in the TCM community: the author of the Lun is regarded as the Medical Sage, while Huangdi (Yellow Emperor) and Qibo, who authored the Jing, are not called Sages. This phenomenon certainly has its reasons. Zhang Zhongjing's contribution to TCM was immense; he saved TCM in times of crisis. The reason TCM has survived to this day is largely due to Zhang Zhongjing's merit. Precisely because of this achievement, he is increasingly referred to as the Medical Sage, and his Lun has also become a Jing. However, Zhang Zhongjing himself was very humble; he did not name his work *Shanghan Zabing Jing*. In this regard, he was wiser than later figures such as Huangfu Mi and Zhang Jiebin. Regarding the above meanings of Jing and Lun, we can explain them using another relationship: Ti (Substance/Essence) and Yong (Function/Application). Jing is the Ti of the Dao, and Lun is the Yong of the Dao. Jing speaks of Ti, and Lun clarifies Yong. Ti is indispensable; without it, all ideals would come to nothing. Therefore, Ti is the foundation, and it is essential. Similarly, Yong is also important. Having Ti without Yong—how would the significance of Ti be manifested? If we only have a strong body but do not exert its function, what is the meaning of this body? It is just a decaying sack! Therefore, this is the relationship between Ti and Yong, and between Jing and Lun. Thus, we know that to master TCM, one must read both Jing and Lun. As for *Shanghan Zabing Lun*, it possesses both aspects of Jing and Lun; it speaks of Ti and clarifies Yong. Should such a work be read? Should it be relied upon?
II. Understanding Yin and Yang to Explore Ultimate Principles
After clarifying the above topics, we come straight to the point. Next, we must raise three questions: First, *Suwen* states: "All febrile diseases nowadays are of the type of Shanghan." Clearly, Febrile Disease is Febrile Disease; why classify it under Shanghan? Cold and Heat are unrelated matters; why is this so? The second question is related to the first. Shanghan is Shanghan, a single disease; why does *Nanjing* say, "Shanghan comprises five types: Wind Strike, Shanghan, Damp-Warmth, Febrile Disease, and Warm Disease"? How can one Shanghan include so many diseases? This is the second issue. Third, why did Zhang Zhongjing use Shanghan as the Jing? Why did later Wang Shuhe directly use "Shanghan" for the book title? These three questions are ones we must clarify before reading *Shanghan Lun*. If these three questions are not cleared up, one cannot comprehend *Shanghan Lun*. So, how can we clarify these three questions? Here, we can borrow a secret formula from Zheng Qin'an, a famous physician from Sichuan in the late Qing Dynasty: "If scholars can explore the ultimate principles on Yin and Yang, they can enter the door of Zhongjing." Therefore, if scholars wish to delve deeply into Zhongjing's discipline, they must place the issue of Yin and Yang in the foremost position.
1. Understanding Yin and Yang