羽流病伤寒。身热头痛。予诊之曰。邪在表。此表实证也。当汗之。以麻黄辈。数日愈。
论曰。或问伤寒因虚。故邪得以入之。今邪在表。何以为表实也。予曰。古人称邪之所凑。
其气必虚。留而不去为病则实。盖邪之入也。始因虚。及邪居中反为实矣。大抵调治伤寒。先要
明表里虚实。能明此四字。则仲景三百九十七法。可坐而定也。何以明之。有表实。有表虚。有
里实。有里虚。有表里俱实。有表里俱虚。予于表里虚实百证歌中。尝论之矣。仲景麻黄汤类。
为表实而设也。桂枝汤类。为表虚而设也。里实。承气之类。里虚。四逆理中之类。表里俱实。
所谓阳盛阴虚。下之则愈也。表里俱虚。所谓阴盛阳虚。汗之则愈也。
酒家朱三者。得伤寒。六七日。自颈以下无汗。手足厥冷。心下满。大便秘结。或者见其逆冷。
又汗出满闷。以为阴证。予诊其脉沉而紧。曰此证诚可疑。然大便结者为虚结也。安得为阴。脉
虽沉紧。为少阴证。然少阴证多矣。是自利未有秘结。予谓此半在表。半在里也。投以小柴胡汤。大便得通而愈。
论曰。伤寒。恶寒。手足冷。心下满。口不欲食。大便 。脉细者。此为阳微结。必有表复
有里也。脉沉亦在里也。汗出为阳微。假令纯阴结。不得复有外证。悉入在里。此为半在表半在
里也。脉虽沉紧。不得为少阴病。所以然者。阴不得有汗。今头汗出。故知非少阴也。可与小柴
胡汤。设不了了者。得屎而解也。难者曰。仲景云病患脉阴阳俱紧。及汗出者。亡阳也。此属少
阴。今云阴不得有汗。何也。今头汗出。故知非少阴也。何以头汗出。则知非少阴。予曰。此说
正是议议处。谓四肢冷。脉沉紧。腹满。全是少阴。然大便硬。头汗出。不得谓少阴。盖头者三
阳所聚。三阳自胸中而还。有头汗出。自是阴虚。故曰汗出为阳微。是阴不得有头汗也。若少阴
有头汗。则九死一生。故仲景平脉法云。心者火也。名火阴。其病。头无汗者可治。有汗者死。
心为手少阴。肾为足少阴。然相与为病。以意逆志。是谓得之。
一位道士患伤寒。身体发热，头痛。我诊断后说：邪气在体表，这是表实证。应当用发汗法治疗，使用麻黄汤之类的方剂，几天就能痊愈。
论述说：有人问，伤寒是因为正气虚弱，所以邪气才得以侵入。现在邪气在体表，为什么说是表实证呢？我说：古人说“邪之所凑，其气必虚”，意思是邪气聚集的地方，正气必然虚弱；但如果邪气停留不去，病势就会表现为实。大概邪气入侵时，起初是因为正气虚，但等到邪气居于体内，反而表现为实证了。大抵调理治疗伤寒，首先要明确表、里、虚、实这四个概念。能明白这四点，那么张仲景的三百九十七种治法，就可以安坐而确定了。怎么来区分呢？有表实，有表虚，有里实，有里虚，有表里俱实，有表里俱虚。我在《表里虚实百证歌》中曾经论述过这些内容。张仲景的麻黄汤类方剂，是为表实证设立的；桂枝汤类方剂，是为表虚证设立的。里实证，用承气汤之类；里虚证，用四逆汤、理中汤之类。表里俱实证，就是所谓的阳盛阴虚，用泻下法就能痊愈；表里俱虚证，就是所谓的阴盛阳虚，用发汗法就能痊愈。
酒商朱三得了伤寒，过了六七天，从颈部以下没有汗，手脚冰凉，胃脘部胀满，大便干结不通。有人看到他有四肢厥冷，又有出汗和胸腹满闷的症状，就认为是阴证。我诊察他的脉象沉而紧，说这个证候确实可疑，但是大便干结的是虚结（此处指因气机郁滞导致的便秘，非纯虚），怎么能算是阴证呢？脉象虽然沉紧，看似少阴病（少阴病），但少阴病大多表现为自发性腹泻，很少有便秘的。我认为这个病证一半在表，一半在里。于是投以小柴胡汤（Minor Bupleurum Decoction），大便通畅后痊愈。
论述说：伤寒病，出现怕冷，手脚凉，胃脘部胀满，嘴里不想吃东西，大便干结，脉象细弱的，这叫作“阳微结”（Yang Wei Jie, a syndrome of slight yang constraint with partial exterior and interior involvement）。这必定是既有表证又有里证。脉沉说明病位在里。出汗是因为阳气微弱（阳微）。假如是纯粹的阴结，就不会再有外在的表证，所有症状都陷入在里，这才是半在表半在里。脉象虽然沉紧，但不能诊断为少阴病。之所以这样，是因为阴证不应该有汗，现在头部出汗，所以知道不是少阴病。可以给予小柴胡汤治疗。如果服药后仍感觉不爽快，通过排便就能解除病邪。质疑的人说：张仲景说病人脉象寸关尺三部都紧，并且出汗的，是亡阳（loss of yang qi），属于少阴病。现在却说阴证不能有汗，这是为什么呢？现在头部出汗，所以知道不是少阴病。为什么头部出汗，就知道不是少阴病呢？我说：这个说法正是需要仔细推敲的地方。如果说四肢冷、脉沉紧、腹部胀满，全是少阴病的表现，但是大便硬、头部出汗，就不能说是少阴病。因为头是三条阳经汇聚的地方，三阳经从胸中返回头部，如果有头部出汗，自然是阴虚（此处指阳郁不能外达，导致上部相对阴虚或阳热上蒸，原文语境强调非少阴寒化之无汗），所以说“出汗为阳微”。阴证是不应该有头部出汗的。如果少阴病出现头部出汗，那就是九死一生。所以张仲景在《平脉法》中说：心属火，名为火脏（注：原文“名火阴”疑为传抄错误或特定术语，通常心为火脏，此处依文意理解为心与少阴的关系），它的病，头没有汗的可以治愈，有汗的会死亡。心属于手少阴经，肾属于足少阴经。然而它们相互关联致病，需要通过心意去推究病机，这才算掌握了要领。
A Daoist priest suffered from Shanghan (Cold Damage). He had fever and headache. I diagnosed him and said: The pathogenic factor is in the exterior; this is an Exterior Excess Syndrome (Biao Shi Zheng). It should be treated by inducing sweating, using formulas such as Mahuang Tang (Ephedra Decoction), and he would recover in a few days.
Discussion: Someone asked, "Shanghan occurs because of deficiency, allowing pathogens to enter. Now that the pathogen is in the exterior, why is it called an Exterior Excess Syndrome?" I replied, "The ancients said, 'Where the pathogenic factor gathers, the Qi must be deficient.' However, if the pathogen remains and does not leave, the disease condition becomes excess. Generally, when a pathogen enters, it initially exploits a deficiency, but once the pathogen resides within, the condition manifests as excess. In general, treating Shanghan requires first clarifying the concepts of Exterior, Interior, Deficiency, and Excess. If one understands these four terms, then Zhang Zhongjing's 397 treatment methods can be mastered with ease. How to distinguish them? There are Exterior Excess, Exterior Deficiency, Interior Excess, Interior Deficiency, simultaneous Exterior and Interior Excess, and simultaneous Exterior and Interior Deficiency. I have discussed these in my 'Song of Hundred Syndromes of Exterior/Interior and Deficiency/Excess'. Zhang Zhongjing's Mahuang Tang-type formulas are designed for Exterior Excess; Guizhi Tang (Cinnamon Twig Decoction)-type formulas are designed for Exterior Deficiency. For Interior Excess, formulas like Chengqi Tang (Gut-Purging Decoction) are used; for Interior Deficiency, Sini Tang (Frigid Extremities Decoction) and Lizhong Tang (Regulate the Middle Decoction) are used. Simultaneous Exterior and Interior Excess refers to what is described as Yang Excess and Yin Deficiency, which is cured by purgation; Simultaneous Exterior and Interior Deficiency refers to Yin Excess and Yang Deficiency, which is cured by diaphoresis."
Zhu San, a wine merchant, contracted Shanghan. After six or seven days, he had no sweat from the neck down, cold hands and feet (Jue Leng), fullness in the epigastrium, and dry, constipated stool. Some physicians, seeing his cold extremities along with sweating and chest/abdominal fullness, considered it a Yin Syndrome. I palpated his pulse, finding it deep and tight, and said, "This syndrome is indeed questionable. However, constipation indicates a 'deficient accumulation' (due to stagnation); how can it be a Yin Syndrome? Although the pulse is deep and tight, resembling Shaoyin Disease (Shaoyin Bing), Shaoyin Disease typically presents with spontaneous diarrhea, rarely constipation. I believe this case involves half-exterior and half-interior pathology." I administered Xiao Chai Hu Tang (Minor Bupleurum Decoction). His bowels moved freely, and he recovered.
Discussion: In Shanghan, symptoms such as aversion to cold, cold hands and feet, epigastric fullness, lack of appetite, constipation, and a fine pulse constitute "Yang Wei Jie" (a syndrome of slight Yang constraint with partial exterior and interior involvement). This implies the presence of both exterior and interior aspects. A deep pulse indicates the pathology is in the interior. Sweating indicates slight Yang deficiency/constraint. If it were a pure Yin accumulation, there would be no exterior symptoms remaining; all signs would be internal, representing a state of being half-exterior and half-interior. Although the pulse is deep and tight, it cannot be diagnosed as Shaoyin Disease. The reason is that Yin syndromes should not present with sweating. Since there is sweating on the head, we know it is not Shaoyin Disease. Xiao Chai Hu Tang may be given. If the patient still feels unwell after administration, relief will come with defecation.
A questioner asked, "Zhang Zhongjing stated that if a patient has a tight pulse at all three positions (Yin-Yang Ju Jin) and sweats, it indicates loss of Yang Qi (Wang Yang) and belongs to Shaoyin. Yet here it says Yin syndromes do not have sweating. Why? Since there is head sweating, we know it is not Shaoyin. Why does head sweating indicate it is not Shaoyin?" I replied, "This point requires careful deliberation. While cold extremities, a deep-tight pulse, and abdominal fullness are characteristic of Shaoyin, hard stools and head sweating rule out Shaoyin. The head is the gathering place of the three Yang meridians. When Yang Qi returns from the chest to the head, head sweating indicates a relative deficiency of Yin (or constrained Yang steaming upward), hence 'sweating indicates slight Yang [constraint/deficiency].' Yin syndromes should not have head sweating. If a Shaoyin disease presents with head sweating, the prognosis is extremely poor (nine deaths to one survival). Therefore, Zhang Zhongjing wrote in the 'Ping Mai Fa' (Method of Pulse Diagnosis): 'The Heart belongs to Fire... In its disease, if there is no head sweat, it is treatable; if there is head sweat, it is fatal.' The Heart corresponds to the Hand-Shaoyin meridian, and the Kidney to the Foot-Shaoyin meridian. They interact in disease; one must use intuitive reasoning to grasp the underlying mechanism."