三阳伤寒，俱有表证，至于三阴，既无表证可据，而又不必一日太阳、二日阳明循经而传，卒然直中，无拘太少，
今试有人卒然患得三阴条脉证，医者诊视，将不知目为何病，无论治之也。故有谓南地无伤寒者，非无伤寒，实有之而
难于识，难于治也。寒者，天地之一气，《伤寒》者，举一以名书，一百一十三方，果皆治寒之剂哉？犹鲁史错举四时而
名《春秋》也。窃谓伤寒一证，不特霜降以后，春分以前有之，即三时皆有之，不过因时易名，春温、夏暑，其证治已
全具于三百九十七法中，在学人能通其变耳。是《伤寒》实备六气之治，厥后或专论温热，或专主三焦，或主心营肺卫，
要不过《伤寒》中之一气一经，未足以窥全豹也。读书贵在参悟，不可如小僧缚律。如邪中三阴，不必皆寒，故三阴亦
有热下证；直中三阴，多兼内伤，故三阴每多温补证。又况外感不出六经，内伤无过五脏，然则《伤寒》一书，并可以
概杂病，何时何地无之哉？溯心源于长沙，当必沉潜反复于其书，犹必详审于无表证之治，则官墙虽峻，庶几可窥。
幼科惊症，自喻氏以食、痰、风、惊四字立名，大剖从前之讹，实为确论，叶香岩亦宗之。然更有未尽者，近多冬
令气暖失藏，入春寒温间杂，小儿吸收其邪，先伤肺经，起自寒热气粗，延绵失治，渐从胞络内传，上部虽有微汗，而
痰多、鼻煽、烦躁、神蒙，病家惶惧，辄云变为惊症，动用香开，妄投金石，以致阴液消亡，热势愈张，正不敌邪，肝
风陡动，渐见肢牵、目窜、痉闭、发厥，势多倾败。若于病未猖撅之前，先以辛凉开肺，继以甘寒化热，佐以润剂降痰，
两候自能痊可。此盖温邪陷入，阴液内耗，而动肝风，实非惊恐致病也。若误以惊药治之，恐幼稚之衔冤不少，故为之
一辨。
三阳经受邪的伤寒病，都有表证表现；至于三阴经受邪，既然没有表证可以作为依据，而且也不一定要遵循“第一天太阳经、第二天阳明经”这样按经络顺序传变的规律，而是突然直接侵犯三阴经，不拘泥于少阳和太阴的顺序。
现在假设有人突然患上具有三阴经脉象和症状的疾病，医生进行诊视，将会不知道这是什么病，无论怎么治疗都难以着手。因此有人说南方没有伤寒病，这并不是说真的没有伤寒，而是确实有伤寒，只是难以识别，也难以治疗罢了。
寒，是天地之间的一种气候之气，《伤寒论》这本书，是举出“寒”这一种气来命名全书，书中记载的一百一十三首方剂，难道都是治疗寒证的药剂吗？这就像鲁国的史书错将四季统称为《春秋》一样。
我私下认为，伤寒这一类病症，不仅是在霜降以后、春分以前出现，即使在春季、夏季、秋季这三个季节也都会发生，不过是随着时节不同而名称有所变化而已。春温病、夏暑病的证候和治疗原则，已经完全包含在《伤寒论》的三百九十七法之中，关键在于学习的人能够通晓其变化规律罢了。
所以，《伤寒论》实际上完备了六气（风、寒、暑、湿、燥、火）的治疗法则。后来有的医家专门论述温热病，有的专门主张从三焦辨证，有的主张从心营肺卫辨证，这些都不过是《伤寒论》中某一种气或某一经络的内容，不足以窥见《伤寒论》的全貌。
读书贵在参悟，不可以像小和尚拘泥于戒律那样死板。例如邪气侵入三阴经，不一定都是寒证，所以三阴经也有热性下利证；直中三阴经的病，多兼有内伤因素，所以三阴经病往往多见需要温补的证型。
况且外感病不出六经范围，内伤病不过五脏范畴，那么《伤寒论》一书，也可以概括杂病的治疗，什么时候、什么地方没有杂病呢？追溯医学源头至长沙太守张仲景，应当必定深入反复研读他的著作，尤其要详细审察没有表证情况下的治疗方法，那么虽然官墙高峻（比喻学问深奥），或许可以窥探到门径。
儿科惊风症，自从喻嘉言以食、痰、风、惊四个字确立病名，大大剖析了以前的错误观点，确实是确切的论断，叶天士也遵从这一观点。然而还有未尽之处，近来多在冬季气候温暖导致阳气失于闭藏，进入春季后寒温夹杂，小儿吸入这种邪气，首先损伤肺经，起病表现为寒热交替、呼吸气粗，如果拖延失治，逐渐从胞络内传，上部虽然有微汗，但痰多、鼻翼扇动、烦躁、神志昏蒙，家属惊慌恐惧，往往说是变成了惊风症，于是使用芳香开窍的药物，胡乱投用金石类药物，导致阴液消亡，热势更加嚣张，正气不敌邪气，肝风突然发动，逐渐见到肢体抽搐、眼球上窜、痉挛闭厥、昏厥等症状，病情大多走向败坏。
如果在病情尚未猖獗之前，先用辛凉药物宣开肺气，继用甘寒药物化解热邪，佐以润燥药物降化痰浊，两个阶段自然能够痊愈。这大概是温邪陷入体内，阴液在内耗损，从而引动肝风，实际上并不是因为惊恐致病。如果误用治疗惊风的药物来治疗它，恐怕年幼的孩子遭受的冤屈不少，所以为此进行辨析。
Shaoyang, Yangming, and Taiyang (Taiyang channel syndrome) cold damage diseases all present with exterior syndromes. As for Shaoyin, Jueyin, and Taiyin (Yin channels) cold damage, since there are no exterior syndromes to rely upon, and transmission does not necessarily follow the sequence of "Day 1 Taiyang, Day 2 Yangming" along the channels, but rather strikes directly into the Yin channels suddenly, without being confined to the order of Shaoyang or Taiyin.
Suppose a person suddenly contracts a disease presenting with pulse and symptoms characteristic of the three Yin channels. If a physician examines them, they would not know what disease it is, making treatment difficult regardless of the approach. Thus, some claim that there is no cold damage in the southern regions. This is not to say that cold damage truly does not exist, but rather that it does exist, yet is difficult to identify and difficult to treat.
Cold is one of the qi (vital energies) of heaven and earth. *Shanghan Lun* (Treatise on Cold Damage) uses "cold" as a representative term to name the book. Do the 113 prescriptions contained therein all serve only to treat cold syndromes? It is akin to the Spring and Autumn Annals (*Chunqiu*), a history of Lu, which erroneously uses the names of two seasons to encompass all four.
I privately hold that cold damage syndromes occur not only after Frost Descent (*Shuangjiang*) and before Spring Equinox (*Chunfen*), but also during the other three seasons (Spring, Summer, Autumn). The names merely change according to the season. The syndromes and treatments for Spring Warmth (*Chunwen*) and Summer Heat (*Xia Shu*) are fully contained within the 397 methods of *Shanghan Lun*. It depends on the learner's ability to understand their variations.
Therefore, *Shanghan Lun* actually encompasses the treatment principles for the Six Qi (Wind, Cold, Summer Heat, Dampness, Dryness, Fire). Later physicians either focused exclusively on Warm Heat diseases, or advocated Sanjiao (Triple Burner) differentiation, or emphasized Xin Ying (Heart Nutrient) and Fei Wei (Lung Defensive) differentiation. These approaches represent only one qi or one channel from *Shanghan Lun* and are insufficient to grasp its complete scope.
Reading requires insight and comprehension; one should not be rigidly bound by rules like a novice monk bound by precepts. For instance, when pathogenic factors invade the three Yin channels, it is not always due to cold; thus, the three Yin channels can also present with heat-type dysentery. Direct invasion of the three Yin channels often involves internal injury; therefore, Yin channel diseases frequently present patterns requiring warming and tonification.
Moreover, external contraction diseases do not exceed the Six Channels, and internal injury diseases do not exceed the Five Zang organs. Thus, *Shanghan Lun* can generalize the treatment of miscellaneous diseases. Where and when are there no miscellaneous diseases? Tracing the source of medicine to Zhang Zhongjing (the Prefect of Changsha), one must delve deeply and repeatedly into his work. By carefully examining the treatment of cases lacking exterior syndromes, although the wall may be high (metaphor for profound knowledge), one might glimpse the path.
In pediatrics, the "Jing" (Fright/Convulsion) syndrome was named by Yu Jia Yan (Yu Chang) using the characters Food, Phlegm, Wind, and Fright. He thoroughly analyzed previous errors, offering a definitive argument, which Ye Tianshi (Ye Gui) also followed. However, there are aspects not fully covered. Recently, winter warmth has caused failure to store yang properly. In spring, cold and warm pathogens mix. Children inhale these pathogens, damaging the Lung Channel first. The onset presents with alternating chills and fever, and coarse breathing. If neglected, the pathogen gradually transmits internally via the Bao Luo (Pericardium Collaterals). Although there may be slight sweating on the upper body, there is excessive phlegm, nasal flaring, irritability, and mental cloudiness. Families panic, claiming it has transformed into a "Jing" (Fright/Convulsion) syndrome. They then use aromatic opening agents and recklessly administer mineral-based medicines (such as cinnabar or realgar), leading to the depletion of Yin fluids and an exacerbation of heat. When Zheng Qi (Upright Qi) cannot resist the Xie Qi (Pathogenic Qi), Liver Wind stirs suddenly. Symptoms gradually include limb twitching, eye deviation, spasm and closure, and syncope. The condition often deteriorates severely.
If treated before the pathology becomes rampant, using acrid-cool herbs to open the Lungs, followed by sweet-cold herbs to resolve heat, assisted by moistening agents to descend phlegm, recovery can naturally occur in two stages. This is essentially Warm Pathogens sinking inward, consuming Yin fluids internally, thereby stirring Liver Wind. It is not actually caused by fright. If mistakenly treated with anti-convulsant/fright-calming medicines, young children will suffer unjustly. Hence, this differentiation is provided.