疫证初起，有似伤寒太阳阳明证者。然太阳阳明头痛，不至如破。而疫则头痛如劈，沉不能举。伤寒无汗，而疫则
下体无汗，上身有汗，惟头汗更盛。头为诸阳之首，火性炎上，毒火盘踞于内，五液受其煎熬，热气上腾，如笼上熏蒸
之露。故头汗独多。此又痛虽同而汗独异也。有似少阳而呕者，有似太阴自利者。少阳之呕，胁必痛；疫证之呕，胁不
痛。因内有伏毒，邪火干胃，毒瓦斯上冲，频频而作。太阴自利，腹必满；疫证自利，腹不满。大肠为传送之官，热注大
肠。有下恶垢者，有旁流清水者，有日及数十度者。此又证异而病同也。
余每论热疫不是伤寒。伤寒不发斑疹。或曰∶热疫不是伤寒，固已。至云伤寒不发斑疹，古人何以谓伤寒热未入胃，
下之太早，热乘虚入胃，故发斑；热已入胃，不即下之，热不得泄，亦发斑。斯何谓欤？曰∶古人以温热皆统于伤寒，
故《内经》云∶热病者，伤寒之类也。《难经》分别五种之伤寒，《伤寒论》辨别五种之治法。既云热入胃，纵非温热，
亦是寒邪化热，故可用白虎、三黄、化斑解毒等汤以凉解也。今人不悟此理，而因以自误误人。至论大者为斑，小者为
疹。赤者胃热极，五死一生；紫黑者胃烂，九死一生。余断生死，则又不在斑之大小紫黑，总以其形之松浮紧束为凭耳！
如斑一出，松活浮于皮面，红如朱点纸，黑如墨涂肤，此毒之松活外见者，虽紫黑成片可生；一出虽小如粟，紧束有根，
如履透针，如矢贯的，此毒之有根锢结者，纵不紫黑亦死。苟能细心审量，神明于松浮紧束之间，决生死于临证之顷，
始信余言之不谬也。
疫证在初起阶段，有类似于伤寒中太阳病和阳明病的表现。然而，太阳病和阳明病引起的头痛，不至于像劈开一样剧烈；而疫病则头痛如劈，沉重得无法抬头。伤寒患者通常无汗，而疫病则是下半身无汗，上半身有汗，尤其是头部出汗更为严重。头是诸阳经汇聚之首，火性炎上，毒火盘踞在体内，煎熬五脏之液，热气向上蒸腾，如同笼子上方熏蒸出的露水。因此头部出汗特别多。这又是疼痛虽然相同但出汗情况唯独不同的地方。有的类似少阳病出现呕吐症状，有的类似太阴病出现自发性腹泻。少阳病的呕吐，胁部必定疼痛；疫病的呕吐，胁部不痛。这是因为体内有潜伏的毒邪，邪火侵犯胃腑，毒气上冲，导致频频呕吐。太阴病的自发性腹泻，腹部必定胀满；疫病的自发性腹泻，腹部不胀满。大肠是传导排泄的器官，热邪注入大肠。有的排出恶臭污垢，有的旁流清水，有的一天多达几十次。这又是症状不同但病因相同的例子。
我每次论述热疫病不是伤寒。伤寒不会发斑疹。有人问：热疫病确实不是伤寒，这已经明白了。至于说伤寒不发斑疹，古人为什么说伤寒热邪未入胃，如果过早使用泻下法，热邪乘虚进入胃中，所以发斑；热邪已经入胃，如果不立即使用泻下法，热邪不得宣泄，也会发斑。这是什么意思呢？我说：古人将温热病都统摄在伤寒之下，所以《内经》说：热病，属于伤寒的一类。《难经》区分了五种伤寒，《伤寒论》辨别了五种治法。既然说热邪入胃，纵然不是温热病，也是寒邪转化为热邪，所以可以使用白虎汤、三黄汤、化斑解毒汤等来凉解。今人不明白这个道理，因而自我误导并误导他人。至于论述大者为斑，小者为疹。颜色红的表示胃热极盛，十死一生；颜色紫黑的表示胃烂，十死一生。我判断生死，则又不在于斑的大小或紫黑与否，总是以斑形的松浮或紧束作为依据！如果斑一出，松软鲜活地浮于皮面，红得像朱砂点纸，黑得像墨涂肤，这是毒邪松软活泼外现的表现，即使紫黑成片也可以生还；如果一出就小如粟米，紧束有根，像鞋子穿透针，像箭射中靶心，这是毒邪有根锢结的表现，纵然不紫黑也会死亡。如果能细心审察衡量，在松浮与紧束之间运用神妙之法，在临证之际决断生死，这才相信我的话没有谬误。
In the initial stage of epidemic febrile diseases (Yi Zheng, 疫证), there are manifestations resembling those of Taiyang (Taiyang disease, 太阳病) and Yangming (Yangming disease, 1. 太阳经受邪所致的病证; 2. 阳明经受邪所致的病证) patterns in Cold Damage (Shanghan, 伤寒). However, headache in Taiyang and Yangming patterns does not reach the intensity of being split apart, whereas in epidemic febrile diseases, the headache is as if split open, so severe that lifting the head is difficult. In Cold Damage, there is typically no sweating, whereas in epidemic febrile diseases, there is no sweating on the lower body but sweating on the upper body, with sweating on the head being particularly profuse. The head is the summit of all Yang meridians; Fire has a nature of flaming upward. When toxic heat lodges internally, it boils the fluids of the five Zang organs, causing hot qi to ascend, similar to the dew formed by steaming under a cover. Therefore, sweating on the head is uniquely excessive. This is another instance where the pain is similar but the sweating is distinct. Some cases resemble Shaoyang (Shaoyang disease, 少阳经受邪所致的病证) with vomiting, while others resemble Taiyin (Taiyin disease, 太阴经受邪所致的病证) with spontaneous diarrhea. Vomiting in Shaoyang pattern is accompanied by hypochondriac pain; vomiting in epidemic febrile disease occurs without hypochondriac pain. This is due to latent toxins within, with pathogenic fire invading the Stomach, causing toxic vapors to rush upward, resulting in frequent vomiting. Spontaneous diarrhea in Taiyin pattern is accompanied by abdominal fullness; spontaneous diarrhea in epidemic febrile disease occurs without abdominal fullness. The Large Intestine is the official organ of transmission and conduction. When heat pours into the Large Intestine, some patients pass foul-smelling fecal matter, some have clear liquid flowing from the side, and some may defecate dozens of times a day. This is another instance where symptoms differ but the underlying pathology is the same.
I often argue that Heat Epidemic (Re Yi, 热疫) is not Cold Damage. Cold Damage does not manifest macules (Ban, 斑) or papules (Zhen, 疹). Someone might ask: It is true that Heat Epidemic is not Cold Damage. But regarding the statement that Cold Damage does not manifest macules and papules, why did the ancients say that if heat in Cold Damage has not yet entered the Stomach, premature purgation allows heat to enter the empty Stomach, thus causing macules; and if heat has already entered the Stomach but purgation is not immediate, preventing heat from venting, macules also appear? What does this mean? I say: The ancients subsumed warm-heat diseases under Cold Damage. Thus, the *Neijing* states: "Febrile diseases are a category of Cold Damage." The *Nanjing* distinguishes five types of Cold Damage, and the *Shanghan Lun* differentiates five treatment methods for them. Since it is stated that heat enters the Stomach, even if it is not a warm-heat disease, it is cold pathogen transforming into heat, so cooling and resolving formulas such as Baihu Tang (White Tiger Decoction), Sanhuang Tang (Three Yellows Decoction), and Huaban Jiedu Tang (Macule-Resolving and Toxin-Expelling Decoction) can be used. Modern people fail to understand this principle, thereby misleading themselves and others. Regarding the distinction between macules and papules: large lesions are called macules, small ones are called papules. Red color indicates extreme Stomach heat, with a mortality rate of nine out of ten; purple-black color indicates rotting of the Stomach, with a mortality rate of nine out of ten. My judgment of life and death, however, does not depend on the size or purple-black color of the macules, but solely on whether their appearance is loose and floating (Song Fu, 松浮) or tight and bound (Jin Shu, 紧束)! If macules appear loose, lively, and floating on the skin surface, red like cinnabar dots on paper or black like ink on skin, this indicates that the toxin is loose and actively emerging externally; even if purple-black and confluent, survival is possible. If they appear small like millet grains, tight and bound with roots, like a needle piercing through a shoe or an arrow hitting the target, this indicates that the toxin is rooted and firmly knotted; even if not purple-black, death will occur. If one can carefully examine and weigh these signs, applying divine discernment between looseness/floatiness and tightness/binding, and deciding life and death at the moment of clinical presentation, then one will believe that my words are not erroneous.