（古名疹，今名 。）
痘乃先天之毒，疹属后天之邪。先天止有水火，后天始备五行。产下发声吮乳，肇自后天，是以发声
之时，口中有毒即咽下，而归于阳明。故 之毒瓦斯，发于阳明，上达于肺，出于皮毛。肺主气而外合皮
毛，是以痘毒走于血分，而气以化之为顺， 毒走于气分，而血以和之为顺，若走于血分而见云头紫赤斑
者，逆也。 乃气分之毒，更速于痘，若停留于胃则烂牙龈，阻滞在肺则为鼻扇喘急，发表疏里、清热解
毒，事在良医之临证妙用者也。夫气为阳，血为阴。痘乃精血中毒，故应四时之生长收藏，以合地支之
数； 乃气分之毒，是以一日三烹，三而三之，以应阳九之终。痘发于阴，故宜头面稀疏，不喜独参阳
位； 发于阳，故喜大烹头面，不宜惟在心胸。此人之阴阳血气，应天地自然之道也。男玉师问曰∶相传
痘先出而 后出者为顺，如 在痘先，后要复出，此亦应先天后天之义欤！
葛根 桔梗 荆芥 防风 杏仁 甘草 牛蒡子 橘皮 上方用泉水煎服，再随四时之气而加减用之。
如寒闭者宜麻黄，热闭者宜石膏，食闭者宜枳、朴、山楂。热甚者加黄芩、黄连；毒甚者加白花地丁、西
河柳；渴者加知母；喘者倍杏仁；里实者加葶苈、牵牛。盖痘疹有血气之分，而用药亦宜分别。如大黄、
大戟，血分之泻药也；葶苈、牵牛，气分之泻药也。黄连形垒如连珠，泻心火之药也；黄芩外肌皮而内腐
空，故名空肠，又名腐肠，乃泻肺而清肌表之药也。肺主气而心主血，故清痘之热毒，宜以连为君而芩为
佐，清 之热毒，宜以芩为君而连佐之。又如金银花，花开黄白，藤名忍冬，能启阴气而解气分血分之热
毒，盖黄走血而白走气也，故解痘毒者宜之，而 毒亦可。若夫白花地丁，又专于 证者也。此用药之大
关目，学人引伸触类，微妙无穷。
(Formerly known as *zhen* [rash], now known as *sha* [sand disease].)
The pathogenic factor of variola (smallpox, *dou*) originates from congenital toxicity, whereas the pathogenic factor of sha (*sha*) belongs to acquired evil. Congenital constitution comprises only water and fire, while acquired constitution encompasses the Five Phases (Wu Xing). The initiation of crying and suckling after birth marks the commencement of acquired functions; thus, at the moment of vocalization, any toxic matter in the mouth is swallowed and directed to the Yangming channel. Consequently, the toxic qi of sha erupts from the Yangming channel, ascends to reach the Lung, and manifests through the skin and hair. The Lung governs Qi and corresponds externally to the skin and hair. Therefore, when the toxic factor of variola enters the Blood level, it is favorable for Qi to transform it; conversely, when the toxic factor of sha enters the Qi level, it is favorable for Blood to harmonize it. If the sha toxin invades the Blood level and presents as purple-red macules resembling cloud patterns, this indicates an adverse prognosis.
Sha represents toxicity in the Qi level and progresses more rapidly than variola. If the toxin stagnates in the Stomach, it causes ulceration of the gums; if it obstructs the Lung, it results in nasal flaring and rapid breathing. The treatment involves releasing the exterior and unblocking the interior, clearing heat, and resolving toxicity, which relies on the clinical acumen of a skilled physician.
Qi belongs to Yang, and Blood belongs to Yin. Variola toxin resides in essence and blood; hence, its progression corresponds to the growth, flourishing,收 (harvest/storage), and storage cycles of the four seasons, aligning with the numerical sequence of the Earthly Branches. Sha toxin resides in the Qi level; therefore, it may manifest repeatedly throughout the day ("three cookings"), multiplying three by three, to correspond with the culmination of Yang numbers (Yang Nine). Variola emerges from Yin, so it is preferable for lesions to be sparse on the head and face, avoiding exclusive manifestation in Yang positions (the head and face). Sha emerges from Yang, so it prefers widespread eruption on the head and face, rather than being confined solely to the chest and heart region. This reflects how human Yin-Yang and Qi-Blood follow the natural Dao of Heaven and Earth.
Master Yu of Nan asked: "It is traditionally said that variola appearing first and sha appearing later constitutes a favorable course. If sha appears before variola and then reappears later, does this also conform to the principles of congenital and acquired natures?"
**Prescription:**
Ge Gen (Puerariae Radix), Jie Geng (Platycodonis Radix), Jing Jie (Schizonepetae Herba), Fang Feng (Saposhnikoviae Radix), Xing Ren (Armeniacae Semen Amarum), Gan Cao (Glycyrrhizae Radix et Rhizoma), Niu Bang Zi (Arctii Fructus), Ju Pi (Citri Reticulatae Pericarpium). Decoct these herbs in spring water. Adjust the formula according to the seasonal Qi.
- For cold obstruction, add Ma Huang (Ephedrae Herba).
- For heat obstruction, add Shi Gao (Gypsum Fibrosum).
- For food stagnation obstruction, add Zhi Shi (Aurantii Fructus Immaturus), Hou Po (Magnoliae Officinalis Cortex), and Shan Zha (Crataegi Fructus).
- For severe heat, add Huang Qin (Scutellariae Radix) and Huang Lian (Coptidis Rhizoma).
- For severe toxicity, add Bai Hua Di Ding (Hedyotis Diffusae Herba) and Xi He Liu (Tectari Radix).
- For thirst, add Zhi Mu (Anemarrhenae Rhizoma).
- For wheezing, double the dosage of Xing Ren.
- For excess conditions in the interior, add Ting Li Zi (Lepidii Semen) and Qian Niu Zi (Pharbitidis Semen).
Generally, variola and sha have distinctions between the Blood and Qi levels, and medications should be selected accordingly. For instance, Da Huang (Rhei Radix et Rhizoma) and Da Ji (Euphorbiae Pekinensis Radix) are purgatives for the Blood level; Ting Li Zi and Qian Niu Zi are purgatives for the Qi level. Huang Lian has a clustered shape resembling pearls and is used to purge Heart Fire. Huang Qin has a fibrous outer layer and hollow interior, hence named Kong Chang (Empty Intestine) or Fu Chang (Rotting Intestine); it purges Lung heat and clears the muscle surface. Since the Lung governs Qi and the Heart governs Blood, to clear the heat-toxin of variola, Huang Lian should be the Sovereign herb and Huang Qin the Assistant; to clear the heat-toxin of sha, Huang Qin should be the Sovereign herb and Huang Lian the Assistant.
Furthermore, Jin Yin Hua (Lonicerae Japonicae Flos), which blooms yellow and white and has a vine named Ren Dong (Enduring Winter), can stimulate Yin Qi and resolve heat-toxins in both the Qi and Blood levels. Generally, yellow enters the Blood and white enters the Qi; thus, it is suitable for resolving variola toxin, and also applicable for sha toxin. Bai Hua Di Ding, however, is specifically indicated for sha cases. These are the key principles of medication application. Students who can extend and categorize these principles will find their subtleties infinite.