夫厥者，有阴有阳。初得病身热，三四日后，热气渐深，大便秘结，小便黄赤，或语言
谵妄而反发热者，阳厥也。初得病，身不热，三四日后，阳气渐消，大便软利，小便清白，或语
言低微而不发热者，阴厥也。二证人多凝之，以脉皆沉故也。然阳厥而沉者，脉当有力；阴
厥而沉者，脉当无力也。若阳厥，爪指有时而温；若阴厥，爪指时时常冷也。仲景云∶伤寒
三二日、四五日厥者，必发热，前热者后必厥，厥深者热亦深，当下之，宜承气汤。又云∶
伤寒脉滑而厥者，里有热也，白虎汤主之。仲景云∶伤寒下利清谷，里寒外热，手足厥而脉
微微者。里有寒也，汗出而厥者同。又云∶阴病下利而脉微者，里有寒也，白通汤主之。
一法无脉利不止，白通加猪胆汁，以其咽干而烦也。
以上病急，或尤急，多有此形状等类。
夫足少阴肾经，其直行者，上贯肝膈入肺中，系舌本，肾恶燥，故渴而
引饮。经云∶口燥舌干而渴，尺寸脉俱沉，则知肾受热邪，为阳证也，当下之。
阴证口干舌燥，非热邪侵凌肾经也，乃嗜欲之人，耗散精气，真水涸竭，元气阳中脱（
坎内阳爻是也。）饮食伤冷，变为枯阴，阳从内消者，或不渴，阳游于外者，必渴而欲饮也。然
欲饮，则饮汤而不饮水，或有饮水者，纵与不任，若不忍戒，误多饮者，变由是而生矣。此
等舌干欲饮冷水，抑而与之汤，及得饮汤，胸中快然，其渴即解。若以渴为热，汤能解之乎
？不惟不能解其渴，其热从而愈甚矣。以是知为阴证也，夫何疑之有！
厥证，有阴证和阳证之分。刚患病时身体发热，过了三四天，热邪逐渐深入，大便秘结不通，小便黄赤，或者出现胡言乱语、神志不清且反而发热的，这是阳厥。刚患病时身体不发热，过了三四天，阳气逐渐消损，大便稀软通畅，小便清亮色白，或者说话声音低微且不发热的，这是阴厥。这两种病症的表现容易让人混淆，因为它们的脉象都呈现沉脉。然而，阳厥而见沉脉的，脉象应当有力；阴厥而见沉脉的，脉象应当无力。如果是阳厥，手指脚趾有时是温暖的；如果是阴厥，手指脚趾时常是冰冷的。张仲景说：伤寒病两三天或四五天出现四肢厥冷的，必定伴有发热，先前发热的随后必然出现厥冷，厥冷越严重，体内的热邪也越深，应当用攻下法治疗，适宜使用承气汤。又说：伤寒病脉象滑利而四肢厥冷的，是里有热邪，应当用白虎汤主治。张仲景说：伤寒病下利排出未消化的食物，里寒外热，手足厥冷且脉象微弱的，是里有寒邪，出汗并伴随厥冷的情况与此相同。又说：阴病下利且脉象微弱的，是里有寒邪，应当用白通汤主治。还有一种治法是无脉且下利不止，使用白通加猪胆汁汤，因为其伴有咽干和烦躁的症状。以上这些病情紧急，甚至特别紧急，多有此类症状表现。
足少阴肾经，其直行经脉，向上贯穿肝脏和膈肌进入肺中，联系舌根。肾厌恶燥邪，所以会出现口渴而想要饮水的症状。医经说：口燥舌干而渴，寸脉尺脉都呈现沉脉，由此可知是肾受热邪侵袭，属于阳证，应当用攻下法治疗。阴证出现的口干舌燥，并不是热邪侵扰肾经所致，而是由于纵欲之人，耗散精气，导致真水枯竭，元气在阳中脱失（即坎卦中的阳爻）。饮食损伤生冷，变为枯阴之证，阳气从内部消减的，或许不渴；阳气浮游于体外的，必定口渴而想要饮水。然而，想要饮水时，只喝热水而不喝冷水，或者有喝冷水的，即使身体不能承受，如果忍不住戒律，错误地多喝，病变就会由此产生。这类人舌干想要饮用冷水，强行压制并给他们喝热水，等到喝了热水后，胸中感到舒畅，口渴随即解除。如果把这种口渴当作热证，热水能解除它吗？不仅不能解除口渴，热邪反而会更加严重。因此知道这是阴证，还有什么可怀疑的呢！
Jue syndrome (Cold Extremities Syndrome) has both Yin and Yang types. When the disease first begins, if the body is hot, and after three or four days, the heat pathogen gradually deepens, resulting in constipation, yellowish-red urine, or delirious speech accompanied by fever, this is Yang Jue (Yang Cold Extremities). If upon onset the body is not hot, and after three or four days, Yang Qi gradually diminishes, leading to soft and loose stools, clear and white urine, or low-voiced speech without fever, this is Yin Jue (Yin Cold Extremities). These two presentations are often confused because both present with a Chen pulse (Deep Pulse). However, in Yang Jue with a Deep pulse, the pulse should be forceful; in Yin Jue with a Deep pulse, the pulse should be weak. In Yang Jue, the fingertips may occasionally become warm; in Yin Jue, the fingertips are constantly cold. Zhang Zhongjing stated: "In Shanghan (Cold Damage), if Jue occurs on the second or third day, or fourth or fifth day, it must be accompanied by fever. Fever preceding Jue implies that the deeper the Jue, the deeper the internal heat; this requires purgation, suitable for Chengqi Tang." He also stated: "In Shanghan, if the pulse is slippery and there is Jue, there is heat inside; Baihu Tang should govern it." Zhang Zhongjing further stated: "In Shanghan, if there is diarrhea with undigested food, interior cold with exterior heat, cold extremities, and a faint pulse, this indicates interior cold. Sweating accompanied by Jue is similar." He also said: "In Yin diseases, if there is diarrhea and a faint pulse, there is interior cold; Baitong Tang should govern it." Another method involves using Baitong Tang plus Pig Bile when there is no pulse and diarrhea persists, due to accompanying dry throat and irritability. The above conditions are acute, or even extremely acute, and frequently present with such symptoms.
The direct pathway of the Foot-Shaoyin Kidney Meridian ascends through the liver and diaphragm into the lungs, connecting to the root of the tongue. The Kidney dislikes dryness; therefore, thirst and a desire to drink occur. The Classics state: "Dry mouth and tongue with thirst, combined with both Cun (Inch) and Chi (Cubit) pulses being Deep, indicates that the Kidney is affected by Heat Pathogens, constituting a Yang syndrome, which requires purgation." Dry mouth and tongue in Yin syndromes are not caused by Heat Pathogens invading the Kidney Meridian, but rather result from individuals indulging in desires, depleting Essence and Qi, causing the True Water to dry up and Yuan Qi (Original Qi) to escape from within Yang (represented by the Yang line in the Kan trigram). Dietary injury from cold foods transforms into Withered Yin, where Yang dissipates internally; such cases may not feel thirsty. However, if Yang wanders externally, there will certainly be thirst and a desire to drink. Yet, those desiring to drink prefer hot water over cold water. Even if some attempt to drink cold water, if they cannot tolerate it but fail to restrain themselves and drink excessively, complications arise. For those with dry tongues desiring cold water, suppressing this urge and providing hot water brings relief in the chest once consumed, resolving the thirst immediately. If one mistakes this thirst for Heat, can hot water resolve it? Not only will it not resolve the thirst, but the heat will intensify. Thus, we know this is a Yin syndrome; what doubt remains!