夫阴阳交媾，火毒遗焉。男子阳盛，则淫火中于气，而为麻毒发于六腑，腑属阳而
为气，故疹有形而无汗。是以发热之初，大与血分煎熬，首尾并宜滋阴补血为主，不可
一毫动气。女子阴盛，则淫火中于血而为痘毒，发于五脏，脏属阴而主血，故痘有形而
有浆，是以发热之初大与气分搏击，治宜凉血补气为主。此以痘疹大概言之，然气血虚
实不同，未可一例而断也。凡看麻疹之法，多于耳后项上腰腿先见，其顶尖而不长，其
形小而匀净，色红者，兼火化也，宜用牛蒡、连翘、升麻、骨皮、知母之类。色白
者，血不足也，尤宜当归、赤芍、红花之类。色紫干燥暗晦者，火盛毒炽也，宜发表
解毒，而兼滋阴凉血，则热自除。所谓养阴退阳也。若至黑色者，则热毒炽极不治，惟
下之以图万一。凡疹出之际，功忌风寒生冷，否则，皮肤闭塞，毒瓦斯壅滞，遂变浑身
青紫，或复隐没，毒反内攻，烦躁腹痛，气喘闷乱，危亡顷至矣。若初出反没，未见恶
症者，重加表发，或有得生，然诸斑疹虽属阳症实多内，内伤乳食脾胃不足，是以荣气
逆行而然，故虚火内炽，灼其阴覆于外，火内炽者，阴已亏极也。阴覆外者，阳亦外走也。
（张）按∶古人以疹属少阴心火，以其色赤也，故多乘肺而见咳嗽诸症。斑属阳明胃
火，以胃主肌肉也。只疹多实热，斑有假阳为定论，然斑疹总属腑症，为血之余而疹
亦见于肌肉有形无汁者也。近来发热日久而见疹者，亦不外乎荣分热极，阴血沸腾，即
属斑类，故不必以斑疹分，但当以虚实判，实者正治，虚者从治，斑之实者，即以古人
治疹之法治斑，疹之虚者，即以治斑之假阳者治疹，天之气化转薄，人禀元气愈亏，即
病之实者，邪气实非真实也。病一退而正气即虚，乃真虚也。今医徒守古人治疹多实热
之论，寒凉肆进，壮实者，根本原固，故中标症清解而即愈，怯弱者、不耐疾病，经此
多日壮热，早已阴亏气弱，再加疏表解毒寒
凉，以有形有余之药，攻无形所变之虚，不知阳毒之有余，实由阴血之不足，舍其实在
汤，去人参而用治麻疹之危困者，属有神效，可见难作实热为定论明
阴阳二气交合，火毒便遗留其中。男子阳气偏盛，淫火侵袭气分，导致麻毒发于六腑；六腑属阳而主气，所以麻疹有形但无汗出。因此在发热初期，主要与血分相互煎熬，从头到尾都应以滋阴补血为主，绝不能丝毫扰动气机。女子阴气偏盛，淫火侵袭血分，导致痘毒发于五脏；五脏属阴而主血，所以痘疹有形且有浆液，因此在发热初期主要与气分搏击，治疗应以凉血补气为主。这是从痘疹的一般情况来说的，然而气血虚实各不相同，不能一概而论。
大凡观察麻疹的方法，多在耳后、颈部、腰部和腿部先出现。如果疹点顶尖但不长高，形状小而均匀洁净，颜色红的，是兼有火化（火热之邪），宜用牛蒡子、连翘、升麻、地骨皮、知母之类的药物。颜色白的，是血不足，尤其适宜用当归、赤芍、红花之类的药物。颜色紫暗、干燥晦暗的，是火盛毒炽，宜用发表解毒之法，并兼用滋阴凉血的药物，那么热邪自然消除。这就是所谓的“养阴退阳”。如果变成黑色的，则是热毒极盛，难以治愈，只有用泻下法来争取万分之一的希望。
凡是疹子发出的时候，最忌讳风寒和生冷食物，否则会导致皮肤闭塞，毒气壅滞，于是全身变为青紫色，或者疹子重新隐没，毒气反而内攻，出现烦躁、腹痛、气喘闷乱等症状，危险立刻到来。如果刚发出就隐没，而没有见到其他恶症，加重发散透表的药量，或许还有生机。然而各种斑疹虽然多属于阳证，实际上多有内伤乳食、脾胃不足的情况，因此营气逆行所致。所以虚火在内炽盛，灼烧阴液反映于外；火在内炽盛，说明阴液已经极度亏损；阴液反映于外，说明阳气也向外走散。
张氏按语：古人认为疹属于少阴心火，因为其颜色红，所以多乘袭肺脏而出现咳嗽等症状。斑属于阳明胃火，因为胃主肌肉。只有疹多属实热，斑有假阳，这是定论。然而斑疹总属于腑症，是血的余气，疹也是见于肌肉，有形而无汁液。近来发热日久才见疹子的，也不外乎营分热极，阴血沸腾，即属于斑类，所以不必以斑和疹来区分，只应当以虚实来判断。实证用正治法，虚证用从治法。斑的实证，就用古人治疹的方法来治斑；疹的虚证，就用治斑的假阳方法来治疹。天的气化逐渐变薄，人禀受的元气日益亏损，即使病是实证，邪气实也不是真正的实。病势一退，正气就虚弱，这才是真正的虚。现在的医生死守古人治疹多属实热的理论，肆意使用寒凉药物。身体强壮的人，根本原本坚固，所以中了轻症的清解法就痊愈了；体弱的人，不耐受疾病，经过多日的壮热，早已阴亏气弱，再加上疏表解毒的寒凉药，用有形有余的药物，去攻打无形所变的虚损，不知道阳毒的有余，实际上是由于阴血的不足。舍弃其实在的汤药，去掉人参而使用治疗麻疹危困情况的药物，却声称有神效，可见不能把难作实热当作定论。
When Yin and Yang interact, fire toxins remain. In men, who are predominantly Yang, excessive fire invades the Qi level, causing measles toxins to manifest in the Six Fu Organs (Six Bowels). Since the Fu Organs belong to Yang and govern Qi, rashes appear with form but without sweat. Therefore, at the onset of fever, there is intense interaction with the Blood level; treatment from beginning to end should primarily focus on nourishing Yin and tonifying Blood, avoiding any disturbance to Qi. In women, who are predominantly Yin, excessive fire invades the Blood level, causing smallpox toxins to manifest in the Five Zang Organs (Five Viscera). Since the Zang Organs belong to Yin and govern Blood, pustules appear with form and contain pus. Thus, at the onset of fever, there is intense interaction with the Qi level; treatment should primarily focus on cooling Blood and tonifying Qi. This describes the general principles for smallpox and measles; however, since Qi and Blood conditions vary in deficiency and excess, one cannot apply a single rule universally.
In observing measles, lesions typically first appear behind the ears, on the neck, waist, and legs. If the rash tips are pointed but not elevated, small, uniform, and clean, with a red color, it indicates an accompanying Fire transformation. Treatment should utilize herbs such as *Arctii Fructus* (Niubangzi), *Forsythiae Fructus* (Lianqiao), *Bupleuri Radix* (Shengma), *Paeceae Cortex* (Gupi), and *Anemarrhenae Rhizoma* (Zhimu). If the color is white, it indicates Blood deficiency; herbs such as *Angelicae Sinensis Radix* (Danggui), *Paeoniae Rubra Radix* (Chishao), and *Carthami Flos* (Honghua) are particularly suitable. If the color is purple, dry, dark, and dull, it indicates excessive Fire and rampant toxin. The treatment should involve releasing the exterior and resolving toxins, combined with nourishing Yin and cooling Blood, so that heat will naturally subside. This is referred to as "nourishing Yin to retreat Yang." If the color turns black, the heat toxin is extremely severe and difficult to treat; only purgation may offer a slim chance of survival.
During the eruption of rashes, exposure to wind-cold and consumption of raw/cold foods must be strictly avoided. Otherwise, skin pores close, trapping toxic gases, leading to cyanosis of the whole body or the re-absorption of rashes. Toxins may attack internally, causing restlessness, abdominal pain, wheezing, and confusion, leading to imminent death. If rashes emerge and then disappear immediately, without other malignant symptoms, increasing the dosage of diaphoretic agents may save the patient. Although most maculopapular eruptions belong to Yang syndromes, they often stem from internal injury due to improper diet, spleen-stomach deficiency, causing Ying-Qi to flow retrograde. Thus, deficient fire blazes internally, scorching Yin fluids which manifest externally. Internal blazing fire indicates extreme Yin deficiency; external manifestation of Yin indicates Yang also escaping outward.
Commentary by Zhang: Ancients attributed measles to Shaoyin Heart Fire due to their red color, noting they often affect the Lung, presenting with coughs. Macules were attributed to Yangming Stomach Fire, as the Stomach governs muscles. It was established that measles are mostly Excess-Heat, while macules may present as False Yang. However, both macules and rashes generally belong to Fu organ syndromes, representing surplus Blood; rashes appear on muscles with form but no fluid. Recently, cases where fever persists for days before rash appearance are due to extreme heat in the Ying level and boiling Yin blood, resembling macules. Therefore, differentiation should not rely on distinguishing between macules and rashes, but rather on Deficiency and Excess. Excess patterns require direct treatment; Deficiency patterns require following treatment. For Excess macules, use ancient methods for treating measles; for Deficient measles, use methods for False Yang macules. As heavenly Qi becomes thinner and human Yuan Qi diminishes, even apparent Excess syndromes are not truly Excess. Once the pathogen recedes, Zheng Qi (Upright Qi) becomes deficient, which is true Deficiency. Modern physicians blindly adhere to the theory that measles are mostly Excess-Heat, administering cold-cooling drugs indiscriminately. Robust individuals, having solid roots, recover quickly from mild clearing treatments. Weak individuals, already suffering from Yin deficiency and Qi weakness after prolonged high fever, suffer further from diaphoretic, detoxifying, and cold-cooling herbs. Using substantial, draining herbs to attack intangible Deficiency ignores that apparent Excess Yang toxin stems from Yin Blood insufficiency. Discarding appropriate decoctions and Ginseng (*Ren Shen*) in favor of dangerous measles protocols, yet claiming miraculous effects, proves that assuming all difficult cases are Excess-Heat is incorrect.