病证阴阳疑似，最难辨别。即如厥有阴阳二证，李士材谓阴厥脉沉弱，指甲青而冷，阳
厥脉
沉滑，指甲红而温，以此为辨。蒲城王竹坪先生（梦祖）《伤寒撮要》采之，以为此说最精，
留心体验之，百不一失。然观《续名医类案·疫门》载，施幼升六月患时疫，口燥舌干，苔
刺如锋，咽喉肿痛，心腹胀满，按之痛甚，渴思冰水，小便赤涩，得涓滴则痛甚，此当急下
之证也，惟通身肌表如冰，指甲青黑，六脉如丝，寻之则有，按之则无，医者引陶氏《全生
集》以为阳证，但手足厥逆，若冷过肘膝，便是阴证，况通身微冷乎？又陶氏谓阴阳二证，
全在脉之有力无力中分，今已脉微欲绝，按之如无，比无力更甚，遂进附子汤，烦躁之极，
不超时竟殒。观此知阴证似阳，又未可以脉沉弱、指甲青冷为凭。余按∶成无己曰∶丹厥若
始得之，手足便厥而不温者，是阴经受邪，阳气不足，可用四逆汤。若手足自热而至温，从
四逆而至逆者，传经之邪也，四逆散主之。此说辨别，至为精审，又凡六气之感，异于伤寒
之传经者，惟舌较为可凭，阴证亦有黑苔、焦黄苔，然其苔必浮胖，或滑润而不枯，此等处
非细心体察，鲜不致误。（上海王协中敬义《疫疠溯源》载∶吴门汪姓患疫症，适当盛暑，
体厥四肢冷极，脉虚，医用参附并四逆等药，遂至危殆，及延余诊，见其咬碎唇舌，周身赤
斑成片，形倦而口中谵妄不成语句，脉参伍极乱，已无下手处矣。以此合魏案观之，知阳证
阴脉，误投温热，必至杀人，可不惧哉？）
上所述通身肌表如冷，指甲青黑，六脉如丝，进附子汤而殒，此阳证似阴，误作阴证治
而死
也。亦有阴证似阳，误作阳证治而死者，黄退庵《证治指要》云∶一妇小产后，身作大热，
舌黄脉大，口干，大便多日不解，医者不辨其假，而用白虎汤一服，便通热缓，病家大
悦。
余诊之，谓此乃格阳于上，其方不可再服，必当温补。问∶既系虚证，何昨日服药大便通热
势解耶？余曰∶此大便之结，如寒月水泽，腹坚其通者，几微元阳为寒凉所逼而出。其热势
减者，亦因寒凉灌濯，暂为退舍。脉象浮大，软如丝絮，急服八珍汤，尚恐无及。其家不信
，医来复诊，见有应效，仍用前方加麦冬、五味子，服后两目直视，循衣摸床，一昼夜而终
。悔无及矣。余按∶肌寒在内而格阳于外，寒在下而格阳于上，此为无根之火，症见烦躁欲
裸形，或欲坐卧泥水中，舌苔淡黄，口燥齿浮，面赤如微酣，（是为戴阳），或两颧浅红，游
移
不定，（异实热证之尽面通红者，叶天士谓戴阳之红，红而娇嫩带白），言语无力，纳少胸闷
，渴欲饮水，或咽喉痛而索水至前，复不能饮，肌表虽大热，而重按则不热，或反觉冷，或
身热反欲得衣，且两足必冷，小便清白，下利清谷，（亦有大便燥结者。）脉沉细，或浮数，
按之欲散，亦有浮大满指，而按之则必无力，是宜温热之剂。如八味丸等药须凉服，从其类
以求之也。
病证的阴阳属性在疑似难辨时，是最难以区分的。就拿厥证来说，有阴厥和阳厥两种证型。李士材认为，阴厥的脉象沉弱，指甲青紫且寒冷；阳厥的脉象沉滑，指甲红润且温暖，以此作为鉴别依据。蒲城的王竹坪先生（名梦祖）在《伤寒撮要》中采纳了这一说法，认为此说最为精辟，只要留心体验，百发百中。
然而，观察《续名医类案·疫门》中记载的案例：施幼升在六月患时行疫病，口燥舌干，舌苔如刺锋般粗糙，咽喉肿痛，心腹胀满，按压时疼痛剧烈，口渴想喝冰水，小便赤红涩痛，哪怕只喝下一滴水也会引起剧烈疼痛，这属于应当急用下法的证候。但是，他全身肌肤表面像冰一样冷，指甲青黑，六部脉象细如丝线，轻取似乎有，重按则无。医生引用陶氏《全生集》的观点，认为是阳证，但指出手足厥逆，如果冷过肘膝，便是阴证，何况是全身微冷呢？另外陶氏还说，阴阳二证的区别，完全在于脉象的有力与无力。如今患者脉微欲绝，重按若无，比无力更严重，于是使用了附子汤，结果患者烦躁至极，不到一小时便死亡了。
看了这个案例就知道，阴证似阳，不能仅仅凭借脉沉弱、指甲青冷来作为判断依据。我分析认为：成无己曾说：“寒厥如果是刚发病，手脚就发凉且不温暖的，这是阴经受邪，阳气不足，可以使用四逆汤。如果手脚从发热逐渐转为温暖，或者从四肢回暖转为厥逆的，这是传经之邪，主治方剂为四逆散。”这种辨别方法，非常精密审慎。此外，凡是六气感受外邪，不同于伤寒的传经变化，只有舌象较为可靠。阴证也会出现黑苔、焦黄苔，但其舌苔必定浮胖，或者滑润而不干枯。这些细节如果不细心体察，很少有不误诊的。（上海王协中敬义在《疫疠溯源》中记载：吴地汪姓患者患瘟疫，正值盛夏，身体厥冷，四肢极冷，脉象虚弱。医生用人参、附子并四逆汤等药物治疗，导致病情危重。后来请我诊治，见其咬碎嘴唇舌头，周身出现成片赤斑，形体疲倦而口中胡言乱语不成语句，脉象参伍不调极其混乱，已经无法下手治疗了。将此案例与魏医生的案例结合来看，可知阳证出现阴脉，如果误投温热药物，必然致人死亡，怎能不恐惧呢？）
上述所述全身肌肤表面如冰冷，指甲青黑，六脉如丝，服用附子汤后死亡的，这是阳证似阴，误当作阴证治疗而死。也有阴证似阳，误当作阳证治疗而死的。黄退庵在《证治指要》中说：一位妇女小产后，身体发大热，舌苔黄，脉象大，口干，大便多日不解。医生不辨别这是假象，使用白虎汤一服后，大便通畅，热势缓解，病家非常高兴。
我诊治后说，这是格阳于上，此方不可再服，必须温补。问：既然是虚证，为什么昨天服药后大便通畅，热势缓解呢？我说：这次大便的结滞，就像寒冬腊月的水泽结冰，腹部坚硬，之所以能通下，是因为微弱的元阳被寒凉药物逼迫而出。热势减退，也是因为寒凉药灌洗，暂时退避。脉象浮大，软如丝絮，急服八珍汤，还恐怕来不及。家属不信，医生再来复诊，见有应验效果，仍用前方加麦冬、五味子，服用后两眼直视，循衣摸床，一昼夜后死亡。后悔也来不及了。
我分析认为：肌表寒冷在内而格拒阳气于外，寒气在下而格拒阳气于上，这是无根之火。症状表现为烦躁想要裸露身体，或者想坐卧在泥水中，舌苔淡黄，口燥齿浮，面色红得像微醉一样（这叫戴阳），或者两颧浅红，游移不定（这与实热证满面通红不同，叶天士说戴阳的红，是红而娇嫩带白色），言语无力，食欲少胸闷，口渴想喝水，或者咽喉痛索要水，但水到面前又喝不下去。肌表虽然大热，但重按却不热，或者反而觉得冷，或者身热反而想要穿衣，并且双脚一定冷，小便清白，下利清谷（也有大便燥结的情况）。脉象沉细，或浮数，重按欲散，也有浮大满指，但重按必然无力，这时适宜使用温热药剂。如八味丸等药须凉服，这是“从其类以求之”的意思。
The differentiation of Yin and Yang in pathological conditions that are similar yet ambiguous is the most difficult. Taking Jue syndrome (Cold Extremities Syndrome) as an example, there are two types: Yin Jue and Yang Jue. Li Shicai stated that in Yin Jue, the pulse is deep and weak, with cyanotic and cold fingernails; whereas in Yang Jue, the pulse is deep and slippery, with red and warm fingernails, using this as the criterion for differentiation. Mr. Wang Zhuping (Mengzu) from Pucheng adopted this view in his *Shanghan Cuoyao* (Essentials of Cold Damage), considering it the most exquisite theory, provided one pays close attention to clinical experience, achieving nearly perfect accuracy.
However, observing the case recorded in *Xu Mingyi Leian* (Continued Cases of Famous Physicians) under the section on Epidemic Diseases: Shi Yousheng contracted a seasonal epidemic in June. He presented with dry mouth and tongue, prickly coating like sharp blades, swollen and painful throat, abdominal distension and fullness with severe pain upon pressure, intense thirst for ice water, dark and scanty urination where even a drop caused severe pain. This was a condition requiring urgent purgation. Yet, his entire body surface felt like ice, fingernails were cyanotic and black, and all six pulses were thread-like, barely perceptible on light palpation and disappearing on heavy pressure. The physician cited Tao's *Quansheng Ji* (Complete Life Collection), arguing it was a Yang syndrome because although there was cold extremities, if the cold extended past elbows and knees, it would be Yin; moreover, the whole body was only slightly cold. Additionally, Tao stated that the distinction between Yin and Yang syndromes lies entirely in whether the pulse is forceful or feeble. Here, the pulse was faint and near extinction, imperceptible on pressure, worse than merely feeble. Consequently, Fuzi Tang (Aconite Decoction) was administered. The patient became extremely restless and died within less than an hour. From this, we know that Yin syndrome may mimic Yang, and one cannot rely solely on a deep-weak pulse and cyanotic-cold nails for judgment.
My analysis: Cheng Wuji said, "If cold Jue begins with immediate coldness of hands and feet without warming, it indicates pathogenic invasion of the Yin meridians and insufficiency of Yang Qi, for which Sini Tang (Frigid Extremities Decoction) is applicable. If hands and feet transition from heat to warmth, or from recovery to coldness again, it indicates transmission of pathogenic factors through the meridians, treated primarily with Sini San (Frigid Extremities Powder)." This method of differentiation is extremely precise. Furthermore, regarding exogenous pathogens of the Six Qi differing from the meridian transmission of Cold Damage, the tongue coating is relatively reliable. Yin syndromes can also present with black or scorched-yellow coatings, but these coatings must be puffy or slippery and moist, not dry. Without careful observation, errors are frequent. (Wang Xiezhong Jingyi of Shanghai, in *Yili Suyuan* (Tracing the Source of Epidemics), recorded: A patient surnamed Wang in Wu suffered from plague during peak summer. His body was cold, limbs extremely cold, and pulse deficient. Doctors used Renshen (Ginseng Root), Fuzi (Prepared Aconite Lateral Root) combined with Sini Tang, leading to critical danger. Upon my consultation, he was biting his lips and tongue, had patches of crimson macules over his body, appeared exhausted, spoke deliriously incoherently, and his pulse was chaotic and irregular, leaving no room for treatment. Comparing this with Dr. Wei's case, it is known that when Yang syndrome presents with Yin pulses, misusing warm-hot medicines will inevitably kill. How can one not fear this?)
The aforementioned case of whole-body surface coldness, cyanotic-black nails, thread-like pulses, death after taking Fuzi Tang, illustrates Yang syndrome mimicking Yin, mistakenly treated as Yin, leading to death. Conversely, there are cases of Yin syndrome mimicking Yang, mistakenly treated as Yang, leading to death. Huang Tui'an in *Zhengzhi Zhiyao* (Essentials of Diagnosis and Treatment) noted: A woman, post-miscarriage, presented with high fever, yellow tongue coating, large pulse, dry mouth, and constipation for many days. The physician failed to recognize the false nature and administered Baihu Tang (White Tiger Decoction). After one dose, bowel movement occurred, and fever subsided, much to the family's delight.
Upon examination, I stated this was "Grid Yang on Upper" (Rebellious Yang floating upwards), and the formula should not be taken again; warm tonification is necessary. Asked: Since it is a deficiency syndrome, why did the bowel move and fever subside after yesterday's medicine? I replied: The constipation was like frozen marshes in winter; the abdomen was hard. The reason it moved was that the minute Yuan Yang (Primal Yang) was forced out by the cold-cooling medicine. The reduction in fever was due to the cold medicine washing away heat temporarily. The pulse was floating and large, soft like silk floss. Urgent administration of Bazhen Tang (Eight-Treasure Decoction) might still be too late. The family disbelieved. When the doctor revisited, seeing the previous effect, he continued the former formula adding Maidong (Ophiopogon Rhizome) and Wuweizi (Schisandra Fruit). After ingestion, the patient stared fixedly, picked at clothes and bed, and died within a day and night. Regret came too late.
My analysis: Cold inside the muscles blocking Yang outward, or cold below blocking Yang upward, constitutes Fire without Root. Symptoms include restlessness with desire to strip naked, or desire to sit/lie in mud/water, pale-yellow tongue coating, dry mouth with floating teeth, facial redness resembling slight intoxication (called Dai Yang / Floating Yang), or shallow redness on cheekbones that migrates (distinct from solid-heat syndrome's full-face redness; Ye Tianshi noted Dai Yang redness is tender and mixed with white), weak speech, poor appetite with chest tightness, thirst for water, or sore throat desiring water but unable to drink once brought, skin feeling hot but cool on deep pressure, or preferring clothing despite heat, cold feet, clear urine, diarrhea with undigested food (though constipation can also occur), deep-thin or floating-rapid pulse that scatters on pressure, or floating-large filling the finger but weak on pressure. In such cases, warm-hot agents are suitable. Medicines like Bawei Wan (Eight-Ingredient Pill) should be taken cool, following the principle of "seeking its kind."