发热无时热翕翕，炊笼腾越热蒸蒸，表热尿白里热赤，外需麻桂内凉承，燥干烦渴
为阳热，厥利外热属阴经，阳热宜清白虎辈，阴热四逆与白通。
【注】发热无时热翕翕，谓发热无休止之时，若合羽外覆之表热也。炊笼腾越热蒸蒸，
谓发热如炊笼蒸蒸内越之里热也。表热，热不在里，故尿白也；里热，故尿赤也。外需
麻桂，谓表热无汗宜麻黄汤，有汗宜桂枝汤。内凉承，谓里热轻者宜凉膈散，重者宜三承
气汤。发热兼口燥、舌干、烦渴者，为阳经之热也，发热兼厥冷、下利清谷者，属阴经
之热也。阳热宜清，白虎解毒辈也。阴热宜温，四逆白通汤也。
【注】翕翕、蒸蒸发热，俱有汗，二证相类。若以翕翕之表热，误为蒸蒸之里热，下
之则逆；若以蒸蒸里热，误为翕翕表热，汗之转伤。翕翕之汗热虽同蒸蒸，扪之自温，不
似蒸蒸之汗热、扪之自有热气透手也。其间或有疑似难辨，又当审小便之白赤，舌苔之
润燥，自可决也。
恶寒表里阴阳辨，发热有汗表为虚，发热无汗表实证，实以麻黄虚桂枝。无热恶寒
发阴里，桂枝加附颇相宜，背寒口和阴附子，口燥渴阳白虎需。
【注】恶寒一证，有表里、阴阳之辨。发热恶寒发于阳表也，有汗宜桂枝汤，无汗宜
麻黄汤。无热恶寒发于阴里也，有汗宜桂枝加附子汤，无汗宜麻黄附子细辛汤。背恶寒
口和，谓口中不燥而和也；阴，谓属少阴也，宜附子汤。背恶寒口燥渴，谓口中燥而渴也；
阳，谓属阳明也，宜白虎加人参汤。
【注】阴阳二经，恶寒虽同，其身有热无热则异也，一则汗之，二则温之。少阴、阳
明之背恶寒虽同，其口中和、口中不和则异也，一则温之，一则清之。恶寒虽属轻微之
证，仲景立法可辨，他可类推矣。
Fever without cessation, feeling warm as if covered by feathers, is exterior heat; fever surging outward like steam from a steamer is interior heat. In exterior heat, urine is clear and white; in interior heat, urine is red. For treatment, exterior patterns require Ma Huang Tang (Ephedra Decoction) or Gui Zhi Tang (Cinnamon Twig Decoction) to induce sweating and release the exterior, while interior heat patterns require Liang Ge San (Cooling the Diaphragm Powder) or Cheng Qi Tang (Ordering the Qi Decoction) formulas to clear heat and purge accumulation. The presence of dry mouth, dry tongue, restlessness, and thirst indicates Yang heat syndrome; the presence of cold extremities, diarrhea with undigested food, and superficial heat indicates a disease pattern of the Yin meridians. Yang heat is suitable for clearing methods such as Bai Hu Tang (White Tiger Decoction), while Yin cold is suitable for warming methods such as Si Ni Tang (Four Reversal Decoction) and Bai Tong Tang (White Pass Decoction).
[Note] "Fever without cessation, feeling warm as if covered by feathers" refers to fever that does not cease, resembling the warmth of feathers covering the body, which is exterior heat. "Steaming like a steamer" refers to interior heat where fever surges outward like steam from within a steamer. Exterior heat means the pathogen is not in the interior, hence urine is clear; interior heat causes urine to be red. "Exterior requires Ma Huang or Gui Zhi" means that for exterior heat without sweat, Ma Huang Tang is appropriate, and for exterior heat with sweat, Gui Zhi Tang is appropriate. "Interior cooling with Cheng Qi" means that for mild interior heat, Liang Ge San is appropriate, and for severe interior heat, the three Cheng Qi Tang formulas are appropriate. Fever accompanied by dry mouth, dry tongue, restlessness, and thirst belongs to the heat of the Yang meridians. Fever accompanied by cold extremities and diarrhea with undigested food belongs to the heat of the Yin meridians. Yang heat should be cleared, using agents like Bai Hu Tang to resolve toxicity. Yin heat should be warmed, using Si Ni Tang and Bai Tong Tang.
[Note] Both Xi Xi (feather-like) fever and Zheng Zheng (steaming) fever present with sweating, making these two conditions similar. If Xi Xi exterior heat is mistaken for Zheng Zheng interior heat and treated with purgation, it will lead to adverse outcomes. If Zheng Zheng interior heat is mistaken for Xi Xi exterior heat and treated with diaphoresis, it will further damage healthy Qi. Although both involve sweating and heat, Xi Xi fever feels only self-warm upon palpation, unlike Zheng Zheng fever, where heat penetrates through the hand upon palpation. When differentiation is difficult due to similarity, one should examine whether the urine is clear or red, and whether the tongue coating is moist or dry, to make a determination.
Chills have distinctions between exterior/interior and Yin/Yang. Fever with sweating indicates an exterior deficiency pattern; fever without sweating indicates an exterior excess pattern. Excess patterns are treated with Ma Huang Tang, and deficiency patterns with Gui Zhi Tang. Absence of fever with chills indicates Yin cold originating in the interior, for which Gui Zhi Jia Fu Zi Tang (Cinnamon Twig Decoction plus Aconite) is quite suitable. Chills in the back with a harmonious mouth (no dryness) indicate a Yin pattern, treated with Fu Zi Tang (Aconite Decoction); dry mouth and thirst indicate a Yang pattern, requiring Bai Hu Jia Ren Shen Tang (White Tiger Decoction plus Ginseng).
[Note] The symptom of chills has distinctions between exterior/interior and Yin/Yang. Concurrent fever and chills originate from Yang exterior patterns; those with sweat are suitable for Gui Zhi Tang, and those without sweat are suitable for Ma Huang Tang. Absence of fever with chills originates from Yin interior patterns; those with sweat are suitable for Gui Zhi Jia Fu Zi Tang, and those without sweat are suitable for Ma Huang Fu Zi Xi Xin Tang (Ephedra, Aconite, and Asarum Decoction). "Back chills with a harmonious mouth" means the mouth is not dry and is harmonious; "Yin" here refers to the Shaoyin meridian, suitable for Fu Zi Tang. "Back chills with dry mouth and thirst" means the mouth is dry and thirsty; "Yang" here refers to the Yangming meridian, suitable for Bai Hu Jia Ren Shen Tang.
[Note] Although both Yin and Yang meridians present with chills, the presence or absence of body heat differs: one is treated with diaphoresis, the other with warming. Although back chills in Shaoyin and Yangming are similar, the state of the mouth (harmonious vs. disharmonious/dry) differs: one is treated with warming, the other with clearing. Although chills are a minor symptom, the laws established by Zhang Zhongjing allow for differentiation, and other cases can be inferred by analogy.