若病在少阴，则有面赤，默默不欲语，但欲寐，或四肢厥逆，或身表如冰石，脉沉细。
若病在厥阴，则四肢厥逆，爪甲青，面黧目黑色，或自汗不止，脉沉弦无力。
若病阴毒证，身表如冰石，四肢厥逆，体如被杖，脉沉细而微，或六至以至八至、九至
、十至而不可数，此等阴证，易为明辨。
惟太阴一证，手足自温，自利不渴，尺寸脉俱沉而弱。仲景云∶宜温之，重则四逆汤。
若脉
浮者桂枝汤。惟此一证，与内感外阳内阴相似。外阳内阴者，即前黄 理中等汤，理中、调
中等丸所治者是也。此等阴证，非古人不言。仲景评脉，首言大浮数动滑，此名阳
也；沉涩弱弦微，此名阴也。非止为外感设，内感之理在其中矣。又云∶阳涩而阴
弦，腹中急痛者，小建中汤主之，则内外所感明矣！至如所言阴病见阳脉者生，阳病见阴脉
者死，此一句即圣人大概之言也。以其阳病见阴脉，故有外阳内阴者，与阳药俱得其生矣。
药当从温，不可遽热，黄 汤之类是也。
上此一条，说古人不尽之意。
或有人饮冷内伤，一身之阳便从内消，身表凉，四肢冷，脉沉细，是谓阴证，则易知之
。若
从外走，身表热，四肢温，头重不欲举，脉浮弦，按之全无力。医者不察，便与表药双解等
，复使汗出，三焦之气绝，以此杀人者多矣！或自服蜜茶及沐浴盖覆，强令汗出，以致变证
不救，如此自杀者亦多矣！身冷脉沉，服调中药，阳自内之外，身体温和而愈。脉浮弦细者
，服调中药，阳从内生，唤入外热，复得脉平温和而愈。此证不可不察也。故仲景云∶太阳
病发热恶寒，热多寒少，脉微弱者，此无阳也，不可发汗。
上此一条，双解、蜜茶、沐浴，阴证皆不可用。
又经云∶脉濡而紧，濡则胃气微，紧则荣中寒，阳微卫中风，发热而恶寒，荣紧卫气冷
，微呕心内烦。医为有大热，解肌又发汗，亡阳虚烦躁，心下苦痞坚，表里俱虚渴，卒起而头眩
，客热在皮肤，怅怏不得眠，不知胃气冷，紧寒在关元。
上此仲景濡紧二脉，即外热内寒证也。
如果病邪在少阴经，就会出现面色发红、沉默不想说话、只想睡觉，或者四肢冰冷逆冷，或者体表像冰石一样寒冷，脉象沉细。
如果病邪在厥阴经，就会出现四肢冰冷逆冷，指甲发青，面色晦暗发黑，眼睛周围色黑，或者自汗不止，脉象沉弦且无力。
如果是阴毒证，体表像冰石一样寒冷，四肢冰冷逆冷，身体感觉像被棍棒打过一样疼痛，脉象沉细而微弱，或者脉搏急促，一息六至甚至八至、九至、十至，快得无法计数，这些阴证，很容易明确辨别。
只有太阴这一种证候，手足自然温暖，自行腹泻但不口渴，寸部和尺部的脉象都沉而弱。张仲景说：适宜用温法治疗，病情重的用四逆汤。
如果脉象浮，就用桂枝汤。只有这一种证候，与“外阳内阴”（外表有热象而内部有寒象）相似。“外阳内阴”的情况，就是前面提到的由黄芪理中汤、理中丸、调中丸等方剂所治疗的病症。这些阴证，并非古人没有论述过。张仲景在评述脉象时，首先说大、浮、数、动、滑这五种脉象，称为阳脉；沉、涩、弱、弦、微这五种脉象，称为阴脉。这不仅仅是为外感病设立的，内伤病的道理也包含在其中了。他又说：阳脉涩而阴脉弦，腹部拘急疼痛的，用小建中汤主治，那么外感和内伤的界限就明确了！至于所说的“阴病见到阳脉者生，阳病见到阴脉者死”，这是圣人的大概之言。因为阳病见到阴脉，所以有“外阳内阴”的情况，使用阳药就能获得生机。药物应当从温性开始，不可立即使用大热之药，黄芪汤之类的方剂就是如此。
以上这一段，阐述了古人不曾详尽说明的意思。
如果有人因饮用冷饮导致内伤，全身的阳气便从内部消损，体表发凉，四肢冰冷，脉象沉细，这被称为阴证，则容易知晓。
如果阳气从内部向外脱散，体表发热，四肢温暖，头重不想抬起，脉象浮弦，按下去完全无力。医生如果不仔细考察，就给患者服用解表的双解类药剂，再次导致出汗，致使三焦之气断绝，因此杀人的情况很多了！或者患者自行服用蜜茶以及沐浴后覆盖保暖，强行令其出汗，以致变证发生而无法救治，这样自杀的也很多了！对于身冷脉沉的患者，服用调中药，阳气从内部通达于外部，身体温和而痊愈。对于脉浮弦细的患者，服用调中药，阳气从内部产生，将外部的虚热引回体内，重新得到平和温和的脉象而痊愈。这种证候不可以不仔细考察。所以张仲景说：太阳病出现发热恶寒，热多寒少，脉象微弱的，这是无阳的表现，不可发汗。
以上这一段，指出双解剂、蜜茶、沐浴等方法，在阴证中都不可使用。
又经文说：脉象濡软而紧，濡脉表示胃气微弱，紧脉表示营分中有寒，阳气微弱卫分受风邪侵袭，发热而恶寒，营分紧束卫气寒冷，轻微呕吐心中烦闷。医生误认为有大热，使用解肌法又发汗，导致亡阳、虚弱、烦躁，心下苦于痞塞坚硬，表里俱虚且口渴，突然起身而头晕目眩，客热停留在皮肤表面，惆怅郁闷无法入睡，不知道胃气寒冷，紧寒邪气位于关元穴处。
以上这一段，张仲景所述的濡脉和紧脉，就是外热内寒的证候。
If the pathogen is in the Shaoyin (Lesser Yin) channel, there will be a red face, silence with reluctance to speak, a desire only to sleep, or cold extremities (Jue Ni), or a body surface as cold as ice and stone, with a deep and fine pulse.
If the pathogen is in the Jueyin (Terminal Yin) channel, there will be cold extremities, cyanosis of the fingernails, a sallow and blackish complexion with dark eyes, or spontaneous sweating that does not stop, with a deep, wiry, and forceless pulse.
In cases of Yin Du (Yin Toxin) syndrome, the body surface is as cold as ice and stone, extremities are cold, the body feels as if beaten by a club, and the pulse is deep, fine, and faint. Alternatively, the pulse may be rapid, beating six, eight, nine, or even ten times per respiration, too fast to count. These types of Yin syndromes are easy to clearly distinguish.
Only in the case of Taiyin (Greater Yin) syndrome are the hands and feet naturally warm, with spontaneous diarrhea without thirst, and both the Cun (inch) and Chi (cubit) pulses are deep and weak. Zhang Zhongjing stated: "It is appropriate to use warming methods; for severe cases, Sini Tang (Four Reversal Decoction)."
If the pulse is floating, Guizhi Tang (Cinnamon Twig Decoction) should be used. Only this specific syndrome resembles "Outer Yang and Inner Yin" (external heat signs with internal cold). "Outer Yang and Inner Yin" refers to conditions treated by Huangqi Lizhong Tang (Astragalus and Middle-Warming Decoction), Lizhong Wan (Middle-Warming Pill), and Tiaozhong Wan (Regulating the Middle Pill) mentioned earlier. These Yin syndromes were not unmentioned by ancient physicians. When evaluating pulses, Zhang Zhongjing first stated that Large, Floating, Rapid, Moving, and Slippery pulses are named Yang; Deep, Choppy, Weak, Wiry, and Faint pulses are named Yin. This is not solely for external contraction; the principles of internal injury are also included therein. He further stated: "When Yang pulses are choppy and Yin pulses are wiry, with acute abdominal pain, Xiaojianzhong Tang (Minor Construct the Middle Decoction) governs it," thereby clarifying the distinction between external and internal contractions! As for the statement "Yin diseases presenting with Yang pulses indicate survival, while Yang diseases presenting with Yin pulses indicate death," this is a general principle of the Sages. Because Yang diseases present with Yin pulses, there are cases of "Outer Yang and Inner Yin"; using Yang-tonifying medicines can restore life. Medications should begin with warmth, not immediately with intense heat; formulas like Huangqi Tang (Astragalus Decoction) exemplify this.
The above paragraph elucidates points not fully expounded by the ancients.
If someone suffers internal injury from drinking cold liquids, the Yang Qi of the whole body dissipates from within. The body surface becomes cool, extremities cold, and the pulse deep and fine; this is termed a Yin syndrome, which is easy to recognize.
However, if Yang Qi escapes outward from the interior, the body surface becomes hot, extremities warm, the head feels heavy and unwilling to be lifted, and the pulse is floating and wiry, yet completely forceless upon pressure. If physicians fail to examine carefully and administer exterior-releasing double-resolving agents, causing further sweating, the Qi of the Sanjiao (Triple Burner) may be severed, leading to many deaths! Or, if patients self-medicate with honey tea, bathe, and cover up, forcing sweat, resulting in transformation of the syndrome that cannot be saved, such self-inflicted deaths are also numerous! For patients with cold bodies and deep pulses, administering Tiaozhong medicine allows Yang Qi to move from the interior to the exterior, resulting in a warm body and recovery. For those with floating, wiry, and fine pulses, administering Tiaozhong medicine generates Yang Qi from within, drawing the external false heat back inward, restoring a平和 (peaceful/warm) pulse and recovery. This syndrome must not go unexamined. Thus, Zhang Zhongjing stated: "In Taiyang disease, if there is fever and aversion to cold, with more heat than cold, and a faint pulse, this indicates a lack of Yang; sweating should not be induced."
The above paragraph indicates that double-resolving agents, honey tea, and bathing are all contraindicated in Yin syndromes.
Furthermore, the classics state: "A pulse that is Soft (Ru) and Tight (Jin); Soft indicates weak Stomach Qi, Tight indicates Cold in the Ying (Nutritive) level. Weak Yang and Wind in the Wei (Defensive) level cause fever and aversion to cold; Ying Tight and Wei Cold cause slight vomiting and internal restlessness. Physicians mistake this for excessive Heat, using muscle-relieving methods and inducing sweat, leading to loss of Yang, deficiency, irritability, and epigastric fullness/hardness. Exterior and Interior are both deficient, accompanied by thirst; rising suddenly causes dizziness. Guest Heat resides on the skin, causing melancholy and insomnia. They do not realize the Stomach Qi is cold, and Tight Cold resides at the Guanyuan point."
The above paragraph describes Zhang Zhongjing's discussion of Soft and Tight pulses, which constitute an "External Heat and Internal Cold" syndrome.