气，阳也。血，阴也。痘之一症，非阳则不能以发，其毒非阴则不能以化其毒，故
必得其阴阳交会，气和血颐也。有阳始会阴，气至血附，根窠既立，而忽中陷者，此
因元气不足，而不能续其后来，是以阴血虽有附气之功而阳气乃无制毒之力，以致陷而
不满，生生之道绝矣。其陷有五。一曰黑陷，二曰血陷，三曰紫陷，四曰白陷，五曰
灰陷。黑陷者，为初出少稀，后出加密，阳会阴之次，因阳气弱而不能续其初出之功，
血无气养，故枯萎而黑陷也。血陷者，血盛于气，气弱不能拘领其毒，久则变而为紫陷
也。紫陷者，为气愈虚而血无气蓄，则毒之盛负载不前，是以血亦为之离去也。白陷者
为气不足，其血亦弱，久则变而为灰陷也。灰陷者，气血衰败而不荣也。此等之陷，一
皆气之缺损使然，如折奇花，少顷生气即绝，则憔淬不荣矣，故宜预为早治。凡见形
平塌，势不起发，摸不硬手，兼或皮皱甚至顶陷，其现症而为吐泻不食，语言不全，此
皆气虚也，即宜保元。如痘形饱满，输廓丰浓，其疮坚硬，或发壮热，或喘痰壅嗽，此
气之实也，治宜清肺和解。如鼻流者清涕、咳嗽恶风、身体战栗、自汗、疮色惨白者，
此气之寒也，宜中和之。如鼻孔干燥皮毛枯槁，咳嗽痰血，或鼻出血，疮色焦紫者，此
气之热也，治宜泻肺。如疮不红活，淡白发痒，不能贯浆，以手摸过，色即转白者，此
血之虚也。如身热不除，或寒热往来，疮色焦紫，口苦舌干，唇青面赤，胁肚作痛者，
此血之实也。如疮色灰惨，血凝不活，面青筋缩，呕吐清水，或泻稀水。如青菜色者，
此血之寒也。若疮色昏暗，发痒，眼珠红赤，大便坚燥，身热易怒，此血之热也。虚
者补之，热者清之，寒者温之，实者抑之，使气血无过不及，但保元汤冲和之气自有蒸
浆化毒之功，又何虑五陷之患哉！
气，属于阳。血，属于阴。痘疹这一病症，如果没有阳气就不能够发出，其毒邪如果没有阴血就不能够化解，所以必须得到阴阳的交会，使气和顺、血滋养。有阳气才能与阴相会，气至则血随之依附，根窠（痘疹根基）既已确立，却忽然中间凹陷的，这是因为元气不足，不能接续后续的力量，因此虽然阴血有依附于气的功能，但阳气却没有制约毒邪的能力，导致痘疹凹陷且不满隆起，生生不息的生命之道断绝了。这种凹陷有五种。第一种叫黑陷，第二种叫血陷，第三种叫紫陷，第四种叫白陷，第五种叫灰陷。黑陷，是指痘疹刚出来时较少较稀，后来出来的加密，在阳气与阴血交会的时候，因为阳气虚弱而不能接续初出时的功效，血液得不到气的滋养，所以枯萎而呈现黑色凹陷。血陷，是血盛于气，气弱不能统摄约束毒邪，时间久了就转变为紫陷。紫陷，是因为气更加虚弱而血没有气来蓄积，那么毒邪的盛大负载使得气血前行受阻，因此血也随之离去。白陷，是因为气不足，其血也弱，时间久了就转变为灰陷。灰陷，是气血衰败而不能荣养。这些种类的凹陷，全都是由于气的缺损造成的，就像折断奇花，片刻之间生气就断绝了，于是憔悴不荣，所以应该预先及早治疗。凡是见到痘形平塌，势头不起发，摸起来不硬手，兼或有皮肤皱缩甚至顶部凹陷，出现的症状有呕吐腹泻、不能进食、言语不全，这都是气虚的表现，就应当使用保元汤（Bao Yuan Tang）。如果痘形饱满，轮廓丰浓，疮口坚硬，或者出现高热，或者气喘痰多壅塞咳嗽，这是气实的表现，治疗应当清肺和解。如果鼻子流清涕、咳嗽怕风、身体战栗、自汗、疮色惨白的，这是气寒的表现，适宜用中和的方法治疗。如果鼻孔干燥、皮毛枯槁、咳嗽带血或鼻出血、疮色焦紫的，这是气热的表现，治疗应当泻肺。如果疮色不红活，淡白且发痒，不能贯浆（化脓结痂），用手摸过后颜色立即转白的，这是血虚的表现。如果身体发热不退，或者寒热往来，疮色焦紫，口苦舌干，嘴唇青紫面色发红，胁肋腹部作痛的，这是血实的表现。如果疮色灰暗惨白，血液凝滞不活泼，面色青紫筋脉收缩，呕吐清水，或者排泄稀水如青菜色的，这是血寒的表现。如果疮色昏暗，发痒，眼珠红赤，大便坚硬燥结，身体发热易怒的，这是血热的表现。虚证用补法，热证用清法，寒证用温法，实证用抑法，使气血不过分也不欠缺，只要保元汤具有冲和之气，自然就有蒸腾化浆、化解毒邪的功效，又何必担忧五种凹陷的祸患呢！
Qi is Yang. Blood is Yin. In the disease of smallpox (or variola), without Yang, it cannot erupt; without Yin, its toxin cannot be transformed. Therefore, there must be an intersection of Yin and Yang, where Qi is harmonious and Blood nourishes. When Yang meets Yin, and Qi arrives causing Blood to attach, once the root base (gen ke) is established, if a sudden central depression occurs, this is due to insufficient Yuan Qi (Original Qi), which fails to sustain subsequent efforts. Thus, although Yin Blood has the function of attaching to Qi, Yang Qi lacks the power to control the toxin, resulting in depression that is neither full nor raised, severing the path of life generation. There are five types of depression: one is Black Depression, two is Blood Depression, three is Purple Depression, four is White Depression, and five is Ashen Depression.
Black Depression refers to when pustules initially appear sparse and few, but later become dense. During the phase of Yang meeting Yin, because Yang Qi is weak and cannot continue the initial efficacy, Blood lacks Qi nourishment, leading withering and black depression.
Blood Depression occurs when Blood is abundant relative to Qi, and weak Qi cannot restrain or lead the toxin; over time, it transforms into Purple Depression.
Purple Depression happens when Qi becomes increasingly deficient and Blood lacks Qi to accumulate it; thus, the overwhelming toxin burdens the system, hindering forward movement, causing Blood to detach.
White Depression is caused by insufficient Qi and concomitant weakness of Blood; over time, it transforms into Ashen Depression.
Ashen Depression signifies the decline and failure of both Qi and Blood, failing to provide nourishment. All these depressions are caused by defects in Qi, similar to breaking a rare flower; within moments, vital energy ceases, leading to withering and lack of luster. Hence, early treatment is necessary.
Whenever the rash appears flat, fails to rise, feels soft upon touch, accompanied by skin wrinkling or even central depression, along with symptoms such as vomiting, diarrhea, inability to eat, and incomplete speech, this indicates Qi Deficiency (Qi Xu). One should immediately use Bao Yuan Tang (Preserve the Origin Decoction).
If the rash is plump, with full contours, hard sores, or presents with high fever, wheezing, phlegm obstruction, and coughing, this indicates Qi Excess (Qi Shi). Treatment should focus on Clearing Lung Heat (Qing Fei) and Harmonizing (He Jie).
If clear nasal discharge, cough, aversion to wind, body tremors, spontaneous sweating, and pale rash color occur, this indicates Cold of Qi (Qi Han). Treatment should aim for Neutralization (Zhong He).
If dry nostrils, withered skin and hair, cough with blood-streaked sputum or epistaxis, and scorched-purple rash color appear, this indicates Heat of Qi (Qi Re). Treatment should involve Draining Lung Heat (Xie Fei).
If the rash is not red and vibrant, appearing pale white and itchy, unable to fill with pus (guan jiang), and turning white immediately upon touch, this indicates Blood Deficiency (Xue Xu).
If persistent body heat, alternating chills and fever, scorched-purple rash, bitter taste, dry tongue, cyanotic lips, flushed face, and pain in the hypochondrium and abdomen occur, this indicates Blood Excess (Xue Shi).
If the rash is dull and grayish-white, blood stagnation without vitality, cyanotic face, contracted tendons, vomiting of clear fluid, or watery diarrhea resembling vegetable juice, this indicates Cold of Blood (Xue Han).
If the rash is dim, itchy, eyes are red, stool is hard and dry, body heat is present, and irritability occurs, this indicates Heat of Blood (Xue Re).
For deficiency, tonify; for heat, clear; for cold, warm; for excess, suppress. By ensuring Qi and Blood are neither excessive nor deficient, Bao Yuan Tang, possessing a balanced and harmonious Qi, will naturally have the function of steaming pus formation and resolving toxins. Why then worry about the perils of the five depressions?