盖太阳病脉似少阴，少阴病证似太阳，所以谓之反，而治当异也。今深究其旨，均自脉沉发热，
以其有头疼，故为太阳病，脉当浮，今反脉不浮而沉者，以里虚久寒，正气衰微所致。今身体疼痛，
故宜救里，使正气内强，逼邪外出，而干姜、生附亦能出汗而解。假使里不虚寒，则见脉浮，而正
属太阳麻黄证也。均自脉沉发热，以其无头疼，故名少阴病，当无热，今反寒邪在表，但皮肤郁闭
而为热，而在里无热，故用麻黄、细辛以发表间之热，附子以温少阴之经。假使寒邪在里，则外必
无热，当见吐利厥逆等证，而属正少阴四逆汤证也。以此观之，表邪浮浅，发热之反尤轻，正气衰
微，脉沉之反为重。此四逆为剂，不为不重于麻黄附子细辛汤也。可见熟附配麻黄，发中有补；生
附配干姜，补中有发。所谓太阳少阴，脉沉发热虽同，而受病有无头疼与用药自别，故并言之耳。
若误治之，其死必矣。
阴阳二厥，治之一差，死证立判。夫阳厥者，先自三阳经气分，因感寒邪，起
于头疼发热，恶寒，已后传进三阳血分，变出四肢厥冷，乍温，大便燥实，谵语发渴，扬手掷足，
不恶寒反怕热，脉沉有力，此见传经热证，谓之阳厥。阳极发厥者，即阳证似阴，外虽有厥冷，内
有热邪耳。盖因大便结实，失下，使血气不通，故手足乍冷乍温也。如火炼金，热极金反化水。水
寒极而成冰，反能载物。厥微热亦微，四逆散；厥深热亦深，大承气。正谓亢则害其物，承乃制其
极也。若医人不识，疑是阴厥，复进热药，如抱薪救火矣。夫阴厥者，因三阴经血分自受寒邪，初
病无身热，无头疼，就便恶寒，四肢厥冷，直至臂胫以上，过乎肘膝不温，引衣蜷卧，不渴，兼或
腹痛吐泻，或战栗，面如刀刮，口吐涎沫，脉沉迟无力。此为阴经直中真阴寒证，不从阳经传入，
谓之阴厥也，轻则理中汤，重则四逆汤温之，勿令误也。
太阳病的脉象似乎像少阴病，少阴病的症状似乎像太阳病，所以称之为“反”，而治疗方法应当不同。现在深入探究其旨意，两者都有脉沉发热的表现，因为伴有头痛，所以诊断为太阳病，脉象应当浮，如今反而不浮而沉，是由于里虚久寒，正气衰微所致。如今身体疼痛，所以适宜救里，使正气在内增强，逼迫邪气外出，而干姜、生附子也能通过出汗而解除病邪。假如里没有虚寒，则会出现脉浮，那就正属于太阳病的麻黄汤证。同样都是脉沉发热，因为没有头痛，所以命名为少阴病，应当没有热象，如今反而是寒邪在体表，只是皮肤郁闭而为热，而在体内没有热，所以用麻黄、细辛来发表间的热，用附子来温通少阴经脉。假如寒邪在体内，那么体外必然没有热，应当出现呕吐、腹泻、四肢厥逆等症状，那就属于正宗的少阴病四逆汤证。从这一点来看，表邪浮浅，发热的“反”象尤其轻微，正气衰微，脉沉的“反”象较为严重。因此四逆汤这一方剂，其重要性并不亚于麻黄附子细辛汤。由此可见，熟附子配伍麻黄，发散中带有补益；生附子配伍干姜，补益中带有发散。所谓太阳病与少阴病，虽然都有脉沉发热，但受病是否有头痛以及用药自然不同，所以一并论述罢了。如果误治，患者必定死亡。
阴阳两种厥逆，治疗上稍有差错，死证立刻判定。所谓的阳厥，起初是三阳经气分感受寒邪，起于头痛发热、恶寒，随后传入三阳血分，变出四肢厥冷、时而温暖、大便燥实、谵语口渴、扬手掷足、不怕冷反而怕热、脉沉有力，这是见到传经的热证，称为阳厥。阳极导致厥逆的，就是阳证似阴，外表虽然有厥冷，内部有热邪罢了。这是因为大便结实，失于攻下，使得气血不通，所以手足时而冷时而温。就像火炼金，热极时金反而化为水。水寒极而成冰，反而能承载物体。厥逆轻微，热也轻微，用四逆散；厥逆深重，热也深重，用大承气汤。正是说亢盛就会危害事物，承受制约才能平息极端。如果医生不认识，怀疑是阴厥，又进服热药，就像抱着柴草去救火一样。所谓的阴厥，是因为三阴经血分直接感受寒邪，初病时没有身热，没有头痛，就伴有恶寒、四肢厥冷，直到手臂和小腿以上，超过肘膝部位不温暖，拉衣蜷缩而卧，不口渴，兼或有腹痛吐泻，或战栗，面色如刀刮般苍白，口吐涎沫，脉沉迟无力。这是阴经直中的真阴寒证，不从阳经传入，称为阴厥，轻症用理中汤，重症用四逆汤温治，不要弄错。
The pulse of Taiyang disease (Disease of the Bladder and Small Intestine channels) resembles that of Shaoyin disease (Disease of the Kidney and Heart channels), and the symptoms of Shaoyin disease resemble those of Taiyang disease; hence it is termed "fan" (reversal/contrary), and the treatment must differ. Upon deep investigation into its principle, both present with a sunken pulse and fever. Because there is headache, it is diagnosed as Taiyang disease, where the pulse should be floating; however, the pulse is now not floating but sunken, caused by deficiency-cold in the interior persisting for a long time and the decline of healthy qi (Zheng Qi). Since there is body pain, it is appropriate to rescue the interior, strengthening the healthy qi internally to force the pathogenic factor outward; in this context, Ganjiang (Dried Ginger) and Sheng Fuzi (Raw Aconite Root) can also induce sweating to resolve the condition. If the interior were not deficient and cold, a floating pulse would appear, and it would strictly belong to the Mahuang Tang (Ephedra Decoction) syndrome of Taiyang disease. Both present with sunken pulse and fever, but because there is no headache, it is named Shaoyin disease, which should lack heat; however, here the cold pathogen is on the exterior, causing heat only due to skin constriction, while there is no heat in the interior. Therefore, Mahuang (Ephedra Herb) and Xixin (Asarum Root) are used to release the heat from the exterior, and Fuzi (Aconite Lateralis Radix Praeparata) is used to warm the Shaoyin meridians. If the cold pathogen were in the interior, there would certainly be no heat on the exterior, and symptoms such as vomiting, diarrhea, and cold limbs would appear, belonging strictly to the Si Ni Tang (Frigid Extremities Decoction) syndrome of true Shaoyin disease. From this perspective, the pathogenic factor on the exterior is shallow, so the "reversal" of fever is particularly mild; whereas the decline of healthy qi makes the "reversal" of the sunken pulse more significant. Thus, the Si Ni Tang formula is not less important than the Mahuang Fuzi Xixin Tang (Ephedra, Prepared Aconite, and Asarum Decoction). It can be seen that prepared Fuzi paired with Mahuang provides tonification within dispersion; raw Fuzi paired with Ganjiang provides dispersion within tonification. Although Taiyang and Shaoyin diseases both present with sunken pulse and fever, the presence or absence of headache distinguishes the pathology and medication, hence they are discussed together. If treated incorrectly, death is certain.
Yin and Yang Jue (cold extremities syndromes), if treated even slightly incorrectly, lead to immediate fatal outcomes. The so-called Yang Jue originates from the Qi level of the Three Yang channels after contracting cold pathogens, starting with headache, fever, and aversion to cold. It then transmits to the Blood level of the Three Yang channels, manifesting as cold extremities, intermittent warmth, dry and hard stools, delirium, thirst, tossing hands and feet, aversion to heat rather than cold, and a sunken, forceful pulse. This indicates a transmitted heat syndrome, termed Yang Jue. Yang extreme leading to Jue means Yang syndrome resembling Yin; although there is coldness externally, there is heat pathogen internally. This is because solidified stool was neglected to be purged, causing obstruction of Qi and blood, resulting in hands and feet alternating between cold and warm. Like fire refining gold, extreme heat causes gold to melt into water. Water freezing into ice can still bear weight. Mild Jue implies mild heat, treated with Si Ni San (Frigid Extremities Powder); deep Jue implies deep heat, treated with Da Cheng Qi Tang (Major Order the Qi Decoction). This refers to the principle that excess leads to harm, and control restores balance. If physicians do not recognize this and suspect Yin Jue, administering hot medicines would be like carrying firewood to put out a fire. The so-called Yin Jue occurs when the Blood level of the Three Yin channels directly contracts cold pathogens. Initially, there is no body heat or headache, only aversion to cold and cold extremities extending up to the arms and calves, with areas above elbows and knees remaining warm. Patients pull clothes over themselves, lie curled up, feel no thirst, and may have abdominal pain, vomiting, diarrhea, tremors, a face pale as if scraped by a knife, salivation, and a sunken, slow, and forceless pulse. This is a true Yin-cold syndrome directly affecting the Yin channels, not transmitting from Yang channels, termed Yin Jue. Mild cases are treated with Li Zhong Tang (Regulate the Middle Decoction), severe cases with Si Ni Tang for warming; errors must be avoided.