凡病皆以虚、实、寒、热四字为大纲，时疫何独不然，但虚、实、寒、热之真者易辨，似者难辨。前所列
时疫表、里诸证，皆实邪、热邪，而实热中亦有虚寒。四损、四不足皆虚邪、寒邪，而虚寒中亦有实热，余于逐条
下已细辨之矣。然有实证似虚，虚证似实，热证似寒，寒
证似热，尤不可不细辨，故复通论而详述之。
所谓实证似虚者，即以表证论之∶头痛、发热，邪在表也，其脉当浮，证当无汗而反自汗，脉无力，用发表药
而身反疼痛，则似虚矣。故人惑于多自汗，而误用桂枝汤者有之；惑于脉无力，而引仲景太阳篇∶发热恶寒，脉微
弱，为无阳，而误用建中汤者有之；惑于身疼痛，而引仲景若不瘥，身体疼痛，当温其里，误用四逆汤者有之。不
知此等证在时疫中，皆在表，实证之似虚者也。其自汗者，疫热自里蒸出于表，非表虚也。其脉无力者，热主散
漫，散漫则脉软，非比寒主收敛而脉紧也。身体反疼者，伏邪自里而渐出于表，非比阳虚不任发表也。此表证之实
证似虚者也。又以半表半里论之∶寒热往来，胸胁满，邪在半表半里也，其脉当弦，其口当渴，而有脉反沉，口不
渴者，则似寒矣。故人惑于脉沉，而以胸胁满为太阴，口不渴为内寒，而误用理中者有之，不知此证在时疫中，皆
半表半里，热证之似寒者也。其脉沉者，邪伏在募原而未出表，故脉不浮，非阳虚也。其不渴者，邪未传变，未入
胃腑，故不能消水，非内寒也。此半表半里之似寒者也。又以里证论之∶口燥咽干不得卧，邪在里也，其脉当滑，
其身当热，其盒饭结，（按滑当作洪。经云，滑者阴气有余也。主痰饮、宿食、吐逆诸证。洪为气血燔灼之候，
主烦、主咽干，表里俱热，二便涩，伤寒阳明经病。）而脉反沉微涩弱，身反四逆厥冷，大便
自利，则全似虚冷矣。人惑于脉之沉微弱涩，而用参、 者有之；惑于厥逆，而用桂、附者有之；惑于自利，而用
参、术、干姜者有之。不知此等证，在时疫皆里热之似寒
也，里实之似虚也。其脉沉微弱涩者，乃邪热结于肠胃，气不达于营卫也。其身反厥冷者，邪热结于里，结于下，
气不达于外，通于上也。其自利者，乃热结旁流也。此里证之实证似虚，热证似寒者也。总之时疫为热因，与风寒
之寒因大异，故脉证虽有似虚、似寒之时，而一辨其为时
疫，则属邪自外至，邪气盛则实，大都反见虚寒假象，明眼人不当为所惑也。
所谓虚证似实者，即以表证论之∶头痛发热身疼痛，自汗脉浮大，邪在表也，而屡用表散清凉药，不惟不减，
其证转甚者，非药力之不到，乃正气不能传药力达表，阴液不能随阳气作汗也，此邪在表时，虚证之似实者也。气
虚者，加参、 于表药即汗；阴虚者，加润剂于表药即汗。若不知其气血之两亏，而宣表不已，势必暴厥而成脱
证矣。更以半表半里论之∶胸胁痛，耳聋，呕吐，如疟状，脉弦，邪在半表半里也，而屡用和解消导药，不惟不
减，其证更加者，非药力之不到，乃中焦胆胃伤而气不运，肝木伤而火燥逆也。此疫邪在半表半里时，虚证之似
实者也。必合四君、六君于和解药中，合四物于清解药中始能战汗而解。若更消导清解不已，必至胃气绝而死。更
以里证论之，舌苔黄黑、裂燥、亡刺，胸、腹、胁、脐硬痛，大小便闭，六脉数大，邪在里也。而屡用攻利药，或
总不得利，或利后更甚，非药力之不峻，乃正气不能传送肠胃，血液不能滋润肠胃也。气虚者，助气以资传送；血
枯者，养阴以藉濡滑，气行津化，方得通利，此疫邪传里时，虚证之似实者也。若不知其亏竭而恣意攻利，必昏沉
萎顿而死。总之药不中病，则伤正气。伤其下，则正气浮越而上逆；伤其中，则正气解散而外张。脉证虽有似实、
似热之时，而一询其来路，若治之太过，则属气从内夺，正气夺则虚，明眼人不当为所惑也。
夫一证而虚实互异，用药稍讹而生死攸分，将以何者为辨证之把柄乎？曰∶以开卷所列气、色、神、脉、舌
苔，辨其是疫与非疫；以曾经误治与未经误治，辨其时疫之为实、为虚，则得其大纲。更细玩前所列各证，条分缕
析之详，则得其细目，则似是而非之证，断不能惑矣。余于前各条下，每证已细辨其虚实，而此复重言以通论之
者，正以前散见于诸条，恐读者忽略，故复总论以提撕其为吃紧处也。至若寒证似热，则伤寒诸证有之，时疫绝
无，故不论及云。
凡是疾病，都以虚、实、寒、热四个字作为总纲，时疫（季节性流行传染病）难道唯独不是这样吗？但是，真正的虚、实、寒、热容易辨别，而似是而非的则难以辨别。前面所列出的时疫表证、里证等各种症状，都属于实邪、热邪，但在实热之中也夹杂着虚寒。四损（久病元气极度亏损）、四不足（气血阴阳亏虚）都属于虚邪、寒邪，但在虚寒之中也夹杂着实热，我在逐条分析时已经详细辨析过了。然而，有实证表现为类似虚证，虚证表现为类似实证，热证表现为类似寒证，寒证表现为类似热证，尤其不能不仔细辨别，所以再次通盘论述并详细说明。
所谓“实证似虚”，就拿表证来说：头痛、发热，说明邪气在体表，脉象应当浮起，症状应当无汗却反而自汗，脉象无力，使用发汗解表的药物后身体反而疼痛，这就看似虚证了。因此，有人被多自汗所迷惑，误用桂枝汤（调和营卫的方剂）；有人被脉象无力所迷惑，引用张仲景《伤寒论》太阳篇中“发热恶寒，脉微弱，为无阳”的说法，误用建中汤（温中补虚的方剂）；有人被身体疼痛所迷惑，引用张仲景“如果不愈，身体疼痛，应当温其里”的说法，误用四逆汤（回阳救逆的方剂）。他们不知道这些证候在时疫中，都位于体表，是实证表现出的类似虚证的假象。那些自汗的，是因为疫热从体内蒸腾向外发散，并非表虚。那些脉象无力的，是因为热邪主散漫，散漫则脉象柔软，不像寒邪主收敛而导致脉象紧束。那些身体反而疼痛的，是因为伏留的邪气从体内逐渐透出体表，不像阳虚不能耐受发汗药一样。这就是表证中实证似虚的情况。
再从半表半里证来分析：忽冷忽热，胸胁部胀满，说明邪气在半表半里之间，脉象应当弦，口应当渴，但如果有脉象反而沉，口不渴的情况，那就看似寒证了。因此，有人被脉沉所迷惑，认为胸胁满是太阴脾经病变，口不渴是内寒，从而误用理中汤（温中散寒的方剂）；他们不知道这些证候在时疫中，都是半表半里的热证，表现出类似寒证的假象。那些脉沉的，是因为邪气潜伏在募原（膜原，指脏腑之间的间隙组织）而未透达体表，所以脉不浮，并非阳虚。那些口不渴的，是因为邪气尚未传变，未进入胃腑，所以不能消耗津液，并非内寒。这就是半表半里证中热证似寒的情况。
再从里证来分析：口干咽燥无法安卧，说明邪气在体内，脉象应当滑，身体应当发热，大便应当干结（按语：此处原文“盒饭”应为“大便”之误，且注家认为“滑”当作“洪”。经典记载：滑脉主阴气有余，常见于痰饮、宿食、呕吐等证；洪脉主气血燔灼，常见于烦渴、咽干、表里俱热、二便不利等证，属伤寒阳明经病），但脉象反而沉微涩弱，身体反而四肢逆冷，大便自行泄泻，这就完全像虚寒证了。有人被脉象沉微弱涩所迷惑，用人参、黄芪等补气药；有人被四肢厥逆所迷惑，用桂枝、附子等温热药；有人被自利（自发性腹泻）所迷惑，用人参、白术、干姜等温补药。他们不知道这些证候在时疫中，都是里热证表现出类似寒证，里实证表现出类似虚证的假象。那些脉象沉微弱涩的，是因为邪热结聚在肠胃，气机不能通达于营卫。那些身体反而厥冷的，是因为邪热结聚在体内、下部，气机不能通达于体表和上部。那些自利的，是因为热结旁流（肠道内有实热积滞，逼迫津液从旁流出导致腹泻）。这就是里证中实证似虚、热证似寒的情况。
总之，时疫的病因是热，与风寒病的寒因大不相同，所以虽然脉证有时看似虚、看似寒，但只要辨明其为时疫，就属于邪气从外侵入，邪气盛则实，大多会反现出虚寒假象，明眼人不应被其所迷惑。
所谓“虚证似实”，就拿表证来说：头痛、发热、身体疼痛、自汗、脉浮大，邪气在体表，但多次使用发散解表和清凉药物，不仅症状不减，反而加重，这不是药力达不到，而是正气虚弱不能推动药力达于体表，阴液不能随着阳气化作汗液，这是邪在体表时，虚证表现出类似实证的假象。气虚的人，在解表药中加入人参、黄芪即可出汗；阴虚的人，在解表药中加入滋润药物即可出汗。如果不知道其气血两亏，而一味宣散发表，势必导致突然昏厥而成脱证。
再从半表半里证来分析：胸胁痛、耳聋、呕吐，像疟疾一样发作，脉弦，邪气在半表半里，但多次使用和解及消导药物，不仅不减，反而加重，这不是药力达不到，而是中焦胆胃受损而气机不运，肝木受损而火气燥逆。这是疫邪在半表半里时，虚证表现出类似实证的假象。必须将四君子汤、六君子汤合入和解药中，将四物汤合入清解药中，才能通过战汗而痊愈。如果继续一味消导清解，必然导致胃气绝灭而死。
再从里证来分析：舌苔黄黑、干裂、生芒刺，胸、腹、胁、脐部位硬痛，大小便闭塞，六脉数大，邪气在体内。但多次使用攻下通便的药物，要么始终不得通利，要么通利后症状更重，这不是药力不够峻猛，而是正气虚弱不能传送糟粕，血液枯涸不能滋润肠道。气虚的人，辅助气机以资助传送；血枯的人，滋养阴液以借助濡润滑利，气行津化，才能通利。这是疫邪传入体内时，虚证表现出类似实证的假象。如果不知道其亏竭而肆意攻下，必然导致神志昏沉、形体萎顿而死。
总之，药不对症就会损伤正气。损伤在下焦，则正气浮越而上逆；损伤在中焦，则正气解散而外张。虽然脉证有时看似实、看似热，但只要询问其治疗经过，若是治疗太过，则属于元气从内部被剥夺，正气被剥夺则虚，明眼人不应被其所迷惑。
一种证候虚实互异，用药稍有差错就关乎生死，那么以什么作为辨证的把握呢？回答说：用卷首所列的气、色、神、脉、舌苔，来辨别是疫病还是非疫病；用曾经误治与未经误治，来辨别时疫是实证还是虚证，就能掌握总纲。再细细玩味前面所列的各证，条理分明地分析其细节，就能掌握细目，那么似是而非的证候，就一定不会被迷惑了。我在前面各条下，对每个证候已经详细辨析了其虚实，而这里又重复论述以作通论的原因，正是因为在前面诸条中分散出现，恐怕读者忽略，所以再次总论以提醒这是关键之处。至于寒证似热，这在伤寒的各种证候中存在，但在时疫中绝无，所以不予讨论。
All diseases are categorized under the four general principles of deficiency (Xu), excess (Shi), cold (Han), and heat (Re). How could seasonal epidemics (Shiyi, seasonal infectious diseases) be an exception? However, true deficiency, excess, cold, and heat are easy to distinguish, whereas those that merely resemble them are difficult. The various exterior and interior syndromes of seasonal epidemics listed previously all belong to excess pathogens and heat pathogens; yet within excess-heat, there can also be deficiency-cold. The "Four Damages" (Sì Sǔn, extreme depletion of Yuan Qi due to chronic illness) and "Four Deficiencies" (Sì Bù Zú, deficiencies of Qi, Blood, Yin, and Yang) all belong to deficiency pathogens and cold pathogens; yet within deficiency-cold, there can also be excess-heat. I have already analyzed these in detail under each specific item. Nevertheless, there are cases where excess manifests as deficiency, deficiency manifests as excess, heat manifests as cold, and cold manifests as heat. These must not fail to be carefully distinguished; therefore, I discuss them comprehensively and describe them in detail here.
What is meant by "excess manifesting as deficiency"? Taking exterior syndromes as an example: headache and fever indicate the pathogen is at the exterior; the pulse should be floating (Fu), and the symptom should be absence of sweating. However, if there is spontaneous sweating, the pulse is forceless, and the body aches more after administering diaphoretic (Fā Biǎo) medications, it appears to be deficiency. Thus, some are confused by excessive spontaneous sweating and mistakenly use Guizhi Tang (Cinnamon Twig Decoction); some are confused by the forceless pulse and cite Zhang Zhongjing's *Treatise on Cold Damage* (Shanghan Lun), Sun Taiyang Chapter: "fever with aversion to cold, weak pulse indicates lack of Yang," and mistakenly use Jianzhong Tang (Middle-Joint Restoring Decoction); some are confused by body aches and cite Zhang Zhongjing: "if not resolved, body aches require warming the interior," and mistakenly use Sini Tang (Frigid Extremities Decoction). They do not realize that in seasonal epidemics, these syndromes are all at the exterior, representing excess manifesting as deficiency. The spontaneous sweating is due to epidemic heat steaming from the interior to the exterior, not exterior deficiency. The forceless pulse is because heat causes dispersion; dispersion leads to a soft pulse, unlike cold which causes contraction leading to a tight pulse. The body aches are due to latent pathogens gradually emerging from the interior to the exterior, unlike Yang deficiency which cannot tolerate diaphoresis. This is how excess manifests as deficiency in exterior syndromes.
Taking half-exterior half-interior syndromes as another example: alternating chills and fever, fullness in the chest and hypochondrium indicate the pathogen is between the exterior and interior; the pulse should wiry (Xian), and the mouth should feel dry/thirsty. However, if the pulse is sunken (Chen) and there is no thirst, it resembles cold. Thus, some are confused by the sunken pulse, attribute chest/hypochondriac fullness to Taiyin syndrome, and no thirst to internal cold, mistakenly using Lizhong Tang (Middle-Warming Decoction). They do not realize that in seasonal epidemics, these are all half-exterior half-interior heat syndromes manifesting as cold. The sunken pulse occurs because the pathogen is latent in the Mao Yuan (Membrane Source/Moyuan) and has not reached the exterior, so the pulse does not float; this is not Yang deficiency. No thirst occurs because the pathogen has not transmitted or entered the Stomach Fu organ, so it does not consume fluids; this is not internal cold. This is how heat manifests as cold in half-exterior half-interior syndromes.
Taking interior syndromes as another example: dry mouth and throat, inability to lie down indicate the pathogen is in the interior; the pulse should slippery (Hua), the body hot, and stool constipated. (Note: The original text contains a typo "box meal" likely for "stool", and commentary suggests "slippery" should be "surging" Hong. Classics state: Slippery pulse indicates excess Yin, common in phlegm-fluids, retained food, vomiting. Surging pulse indicates blazing Qi and Blood, common in irritability, dry throat, exterior-interior heat, difficult urination/defecation, characteristic of Yangming channel disease in Cold Damage.) However, if the pulse is sunken, micro, choppy, and weak, the body is cold in the four extremities, and there is spontaneous diarrhea, it completely resembles deficiency-cold. Some are confused by the sunken, micro, choppy, weak pulse and use Renshen (Ginseng Radix) and Huangqi (Astragali Radix); some are confused by cold extremities and use Guizhi (Cinnamomi Ramulus) and Fuzi (Aconiti Lateralis Radix Praeparata); some are confused by spontaneous diarrhea and use Renshen, Baizhu (Atractylodis Macrocephalae Rhizoma), and Ganjiang (Zingiberis Rhizoma). They do not realize that in seasonal epidemics, these are all interior heat manifesting as cold, and interior excess manifesting as deficiency. The sunken, micro, choppy, weak pulse is due to pathogenic heat knotting in the intestines and stomach, preventing Qi from reaching Ying and Wei. The cold extremities are due to pathogenic heat knotting in the interior/lower part, preventing Qi from reaching the exterior/upper part. The spontaneous diarrhea is due to heat-knotting with side-flow (Re Jie Pang Liu, where heat accumulation forces fluid out). This is how excess manifests as deficiency and heat manifests as cold in interior syndromes.
In summary, the etiology of seasonal epidemics is heat, vastly different from the cold etiology of Wind-Cold diseases. Therefore, although pulses and symptoms may occasionally resemble deficiency or cold, once identified as a seasonal epidemic, it belongs to external pathogens; when pathogens are abundant, it is excess. It mostly presents false images of deficiency and cold. Discerning individuals should not be misled.
What is meant by "deficiency manifesting as excess"? Taking exterior syndromes as an example: headache, fever, body aches, spontaneous sweating, floating-large pulse indicate the pathogen is at the exterior. However, repeated use of dispersing and cooling medications not only fails to reduce symptoms but worsens them. This is not because the medication potency is insufficient, but because Zheng Qi (Upright Qi) is too weak to transmit the medication's power to the exterior, and Yin fluids cannot transform into sweat following Yang Qi. This is how deficiency manifests as excess when the pathogen is at the exterior. For Qi deficiency, adding Renshen and Huangqi to exterior-resolving herbs induces sweating; for Yin deficiency, adding moistening agents to exterior-resolving herbs induces sweating. If one fails to recognize the dual deficiency of Qi and Blood and continues to disperse excessively, sudden collapse (Bao Jue) and exhaustion syndromes will inevitably occur.
Taking half-exterior half-interior syndromes as another example: chest/hypochondriac pain, deafness, vomiting, malaria-like paroxysms, wiry pulse indicate the pathogen is between exterior and interior. However, repeated use of harmonizing and directing-stagnation medications not only fails to help but worsens symptoms. This is not due to insufficient medication potency, but because the Middle Jiao Gallbladder and Stomach are damaged, causing Qi stagnation, and Liver Wood is damaged, causing Fire to rise dryly. This is how deficiency manifests as excess when the epidemic pathogen is in the half-exterior half-interior region. One must combine Sijunzi Tang (Four Gentlemen Decoction) or Liujunzi Tang (Six Gentlemen Decoction) with harmonizing herbs, and Siwu Tang (Four Substances Decoction) with clearing-resolving herbs, to achieve resolution through battle-sweat (Zhan Han). If one continues to use directing-stagnation and clearing-resolving methods excessively, Stomach Qi will perish, leading to death.
Taking interior syndromes as another example: yellow/black tongue coating, cracking, dryness, prickles, hardness/pain in chest/abdomen/hypochondrium/navel, closure of urine and feces, rapid-large pulses indicate the pathogen is in the interior. However, repeated use of purgative medications either results in no relief or worsening after evacuation. This is not because the purgative potency is not harsh enough, but because Zheng Qi is too weak to transport waste in the intestines/stomach, and Blood is too dry to moisten the intestines/stomach. For Qi deficiency, assisting Qi aids transport; for Blood desiccation, nourishing Yin provides lubrication. Only when Qi moves and fluids transform can there be free passage. This is how deficiency manifests as excess when the epidemic pathogen transmits to the interior. If one fails to recognize the depletion and肆意 (recklessly) uses purgatives, mental cloudiness and physical emaciation/collapse will lead to death.
In summary, medication that does not match the pathology damages Zheng Qi. Damage to the Lower Jiao causes Zheng Qi to float upward and rebel; damage to the Middle Jiao causes Zheng Qi to scatter outward. Although pulses and symptoms may sometimes resemble excess or heat, if one inquires into the history of treatment, excessive treatment leads to the deprivation of Qi from within; when Zheng Qi is deprived, it becomes deficiency. Discerning individuals should not be misled.
One syndrome may present differently regarding deficiency and excess; a slight error in medication determines life or death. What serves as the handle for differentiation? Answer: Use the Qi, Color, Spirit, Pulse, and Tongue Coating listed at the beginning to differentiate between epidemic and non-epidemic conditions; use the history of previous mis-treatment versus no mis-treatment to differentiate whether the seasonal epidemic is excess or deficiency. This grasps the general principle. Further careful study of the detailed analysis of various syndromes listed previously allows one to grasp the specifics, ensuring that ambiguous syndromes cannot cause confusion. I have already analyzed the deficiency/excess nature of each syndrome in the previous sections. The reason for reiterating this comprehensive discussion is that since the previous points were scattered across various items, readers might overlook them; thus, a general discussion is provided to highlight these critical points. As for cold manifesting as heat, this exists in various syndromes of Cold Damage, but absolutely does not exist in seasonal epidemics; therefore, it is not discussed here.