夫痘种于三五之枭淫，伏藏于干元之肾窖，肾所主者骨髓也。毒伏于兹，随感而
见。象与药锐相似，火未至也。间寂无声，火既至也。赫然震于宇宙之间，犹镜之取
火，火虽在内，使无日之精光相射，不能发也，是以痘疹未发，则遐迩俱寂，一发则遐
迩俱燃，然此者，岂其如疫疠之相似耶？非也。若说痘疹为时气之所感召则可，若说痘
疹与疫疠无异则不可，疫疠恶症也，自外至内，热是邪火流传，疫毒之气旁敷耳，若痘
疹正病也，自里达表猛热者，为正火。传络者，为正传，但其机之感召，亦本于气运之
火动，盖诸疮非火不发，非金不收，《经》曰∶诸痛痒疮疡皆属于火。”《书》曰∶冬若
温暖，春必发痘，是皆以火动言之。即云从龙，风从火之义也，然痘之发必至三年，五
年而一旺者何也？《经》曰∶其生五，其气三，言形之所存，假五行而运用，征其本
始，从三气以生成。又曰∶三而成天，三而成地，三而成人，故乾坤诸卦，皆数三也。
人在气交之中，莫不因时感气而动三者，万物生成之数，亦积余盈闰，补偏救弊之年
也。毒虽内藏于肾，外必假诸流行，气迎而萌，是气也，岁运有太过不及，天道有乖戾
变常，常此戾气流行之后，则天人相感之气，俱已消弥，必于三年五年，为偏，为
弊，乖戾之气，复感于所，是亦春生秋杀之义，泰否之象也。是以圣人立法，积余成
闰，以正天度，皆在三五也。然有全家尽患，而独有一二不出者何也？盖痘毒既由于
外感时气，此必独能调养，或元气浓，不能感触尔，故曰∶儿禀气虚则出早。气实则出
晚者，此也。然冬温痘发之义何也？盖冬系太阳寒水所至，冬若温暖，是水德不彰，故
厥阴少阴，木火之气反来乘之，而阳气早发，夫痘疹之毒，藏于至阴之下，发于太阳
之经，当其时而动其气，则毒之为感召，乃发于春，故凡冬温，便须预防，凡解毒之
药，及禀气不足，素有疾病者，并宜预治也。
痘毒在婴儿三五个月大时，因淫邪之气侵入而种下，潜伏藏匿于先天之本的肾中，肾所主管的是骨髓。毒邪潜伏在此处，随着外感邪气而显现出来。其形态与药物尖锐之性相似，此时火气尚未到达。平时寂静无声，当火气到来时，便赫然震动于天地之间，就像古代用铜镜聚焦日光取火一样，火虽然在内，但如果如果没有日光的精纯光芒照射，是无法发出来的。因此，痘疹在未发作之前，无论远近都一片寂静；一旦发作，则远近皆如火燃。然而这种情况，难道和瘟疫疫病相似吗？不是这样的。如果说痘疹是由时令气候感召所致是可以的，但如果说痘疹与瘟疫疫病没有区别则是不可以的。瘟疫属于恶症，病邪从外部传入内部，热是邪火流传，疫毒之气向四周扩散；而痘疹是正病，热气由内达表猛烈发出，这是“正火”。传变经络，称为“正传”，但其发病机理的感召，也根本源于运气之火气的变动。大概各种疮疡非火不能发散，非金（收敛肃降之气）不能收束，《黄帝内经》说：“各种疼痛、瘙痒、疮疡都属于火。”《尚书》说：“冬天如果温暖，春天必定爆发痘疹。”这都是从火气发动的角度来说的。这就是所谓“云从龙，风从火”的道理。然而痘毒的发作，往往要经过三年、五年才有一次旺盛期，这是为什么呢？《黄帝内经》说：“五行生万物，三气运化。”意思是形体所存在的物质，借助五行的作用来运行，追溯其本源，是从三气来生成的。又说：“三构成天，三构成地，三构成人。”所以乾坤等卦象，数理都以三为主。人生活在天地气交之中，无不因时节感受气机而动，三数是万物生成的基数，也是积累余数成为闰年，以弥补偏差、纠正弊端的年份。毒邪虽然内藏于肾，但外在必然假借流行之气而萌动。这种气，岁运有太过或不及，天道有乖戾反常的变化。常常在这种乖戾之气流行之后，天人相感的气机都已经消弥，必须等到三年、五年，作为偏差和弊端，乖戾之气再次感应到相应的位置，这也是春生秋杀的意义，以及泰卦与否卦的象征。所以圣人制定法则，积累余数成为闰月，以校正天文历度，都在于三和五。然而为什么全家都患病，却唯独有一两个人不出痘呢？大概是因为痘毒既然由于外感时气所致，这些人必定能够独自调养，或者元气浓厚，不能被邪气感触罢了。所以说：小儿禀受的气虚，出痘就早；气实，出痘就晚，就是这个道理。那么冬天温暖导致痘发的意义是什么呢？大概冬季是太阳寒水当令，如果冬天温暖，就是水的德性不彰显，所以厥阴、少阴的木火之气反而来乘袭克制，导致阳气过早发动。痘疹的毒邪，藏于至阴之下，发于太阳之经，当其时触动其气，那么毒邪的感召，就会在春天发作。所以凡是遇到冬温的气候，就必须提前预防，凡是解毒的药物，以及禀气不足、素有疾病的人，都应该预先治疗。
The variola virus (smallpox pathogen) is implanted during the infant's third to fifth month due to excessive evil qi, and lies dormant in the "kidney cavity" of the primordial origin. The Kidney governs the bone marrow. The toxin lies hidden there and manifests upon external stimulation. Its form resembles the sharpness of medicinal herbs; at this stage, Fire has not yet arrived. It remains silent and still; when Fire arrives, it suddenly shakes the universe. This is like using a bronze mirror to catch fire from the sun: although the fire is within, without the pure light of the sun shining upon it, it cannot ignite. Therefore, before the eruption of smallpox or measles, all around is silent; once erupted, all around burns like fire. However, is this similar to epidemic pestilence? No. It is acceptable to say that smallpox and measles are induced by seasonal climate changes, but it is incorrect to say they are no different from epidemic pestilence. Epidemic pestilence is a malignant condition where pathogens enter from the exterior to the interior; heat is the transmission of evil fire, and the qi of epidemic toxins spreads widely. In contrast, smallpox and measles are proper diseases; the intense heat radiates from the interior to the exterior, which is called "Proper Fire." Transmission through meridians is called "Proper Transmission." However, the mechanism of its induction is fundamentally rooted in the movement of Fire in the Six Qi movements. Generally speaking, sores and ulcers do not erupt without Fire, nor do they heal without Metal (the element of收敛/consolidation). The *Classic* states: "All pain, itching, sores, and ulcers belong to Fire." The *Book of Documents* states: "If winter is warm, smallpox will erupt in spring." All these statements refer to the activation by Fire. This aligns with the principle that "clouds follow the dragon, wind follows fire." But why does the eruption of smallpox reach a peak only every three to five years? The *Classic* states: "It generates five, its qi is three." This means that the existence of forms relies on the operation of the Five Phases; tracing back to the origin, generation occurs through the Three Qi. It also says: "Three constitutes Heaven, three constitutes Earth, and three constitutes Humanity." Thus, the hexagrams of Qian and Kun all use the number three. Humans exist within the intersection of Qi, moving according to seasons and sensing Qi. The number three is the count of the generation of all things, and also represents accumulating surplus to form leap years, correcting deviations and remedying flaws. Although the toxin is stored internally in the Kidney, externally it must rely on circulating Qi to sprout. This Qi varies in excess or deficiency in annual movements, and the Heavenly Dao may exhibit aberrant and abnormal changes. After such aberrant Qi circulates, the Qi connecting Heaven and Humanity dissipates. It takes three to five years for these deviations and flaws to accumulate, allowing aberrant Qi to re-induce corresponding locations. This reflects the meaning of spring generation and autumn killing, and the imagery of Tai (Peace) and Pi (Standstill) hexagrams. Therefore, sages established laws, accumulating surplus to create leap months, to correct celestial degrees, all centered on the numbers three and five. Yet, why might an entire family suffer while one or two individuals remain unaffected? Since the smallpox toxin arises from external seasonal infections, those unaffected likely maintained good self-care or possessed robust Yuan Qi (Primordial Qi), preventing infection. Hence it is said: "Children with deficient congenital Qi erupt early; those with substantial Qi erupt late." What is the significance of winter warmth causing smallpox eruption? Winter is governed by the Taiyang Cold Water phase. If winter is warm, the virtue of Water is not manifest, causing the Wood and Fire Qi of Jueyin and Shaoyin to counter-attack. This leads to premature Yang Qi activation. The toxin of smallpox hides beneath the Extreme Yin and erupts via the Taiyang Meridian. When the season triggers its Qi, the induction of the toxin results in eruption in spring. Therefore, whenever winter warmth occurs, prevention is necessary. For those taking detoxifying herbs, or those with weak congenital Qi or chronic illnesses, preemptive treatment is advisable.