夫天有非时之气，人即有非时之疾。禀赋强浓者，尚得以元气胜之，惟麻痘两症，尽人
不免，每多发于婴儿，则为寰区通病。考先哲传书，详于论痘而略于论麻，盖以麻出六腑，与
痘出五脏者不同，治得其法，可以片言居要，后学不明此意，辄谓治痘难，治麻易，浅试轻
尝，多至草菅人命，良可悲也。壬子岁，自春延及夏秋，凡大村小落，小儿枉折者，不知凡
几。虽曰气数使然，亦半由司命者未得其窍要也。砚丞汇有《麻疹备要》，皆采古人精言良法，
可与明理者证活幼之心源。顷因家君代刻《神灸经纶》一书，请付梓其后，爰志数言于简端。
时咸丰三年岁次癸丑仲夏月双溪吴与九书于聊且粗略之居
疹之为病也，本乎胎毒，感时行 戾之气而发，亦与痘同。但痘出五脏属阴，阴主
血，故有形有浆，其症有寒有热有虚实。疹出于六腑属阳，阳主气，故有形无浆，其症
多实，有热而无寒。症既不同，治法亦异。世咸知痘疹所系于人者甚重，而不知疹之系人
生死者为尤重。盖人当有生之初，受天地之气以成形，干为天阳也，故称乎父，坤为地
阴也，故称乎母。阴阳二气交感，而相火即寓乎其中，所以阴中之火，伏于人之身，发
而为痘，阳中之火，伏于人之身，发而为疹。当其未发，无形可拟，无迹可寻，如石中之
火，必击而后动。及其动也，因人之禀质为轻重，轻者可不治而愈，重者非善治不愈，所
谓先天而天不违者此也。又必因天行之时气为缓急，缓者外邪之来不暴疾，可轻散，可
清解，随表达而不遗；重者外邪之气多暴疾，正气先被其侵伐，内毒蕴结而不出，急当专
力以治其标，使蕴结者乘势而外达，所谓后天而奉天时者此也。苟能悉先天之体，明后
天之用，则周旋折旋，无所往而不得其中矣。
天有不合时节的异常气候，人就会患不合时宜的疾病。禀赋强壮的人，尚且能够凭借元气战胜它，只有麻疹和天花这两种病症，没有人能完全避免，而且多发生于婴儿时期，因此成为遍布天下的通病。考察前代哲人的著作，详细论述天花而简略论述麻疹，大概是因为麻疹发于六腑，与发于五脏的天花不同，治疗方法得当，可以用简练的语言抓住要点。后世学者不明白这个道理，往往认为治痘难、治麻易，浅尝辄止，轻率尝试，导致许多人草菅人命，实在令人悲哀。壬子年（1852年），从春季延续到夏秋，无论大村小落，枉死的小儿不知有多少。虽然说是气数使然，但也有一半原因是因为掌握生杀大权的医生没有掌握其中的关键要领。砚丞汇编了《麻疹备要》，都是采集古人的精辟言论和良好方法，可以与明理之人共同印证救治幼儿的心法渊源。近期因为家父代理刻印《神灸经纶》一书，请求将其附在后面刊行，于是写了几句话放在书的前面。时间是咸丰三年（1853年）农历五月，双溪吴与九写在简陋的居所中。
疹这种病，根源在于胎毒，感受时行的戾气而发作，这也与天花相同。但天花发于五脏属阴，阴主血，所以有形且有脓浆，其症状有寒有热、有虚有实。麻疹发于六腑属阳，阳主气，所以有形无脓浆，其症状多为实证，只有热而没有寒。既然症状不同，治疗方法也就各异。世人都知道痘疹对人的影响很重，却不知道疹对人生死的影响更为严重。大概人在刚出生时，承受天地之气以形成形体，干为天阳，所以称为父；坤为地阴，所以称为母。阴阳二气交感，相火就蕴含在其中，所以阴中之火潜伏在人体内，发作出来就是痘；阳中之火潜伏在人体内，发作出来就是疹。当它们尚未发作时，没有形状可以比拟，没有踪迹可以寻找，就像石头中的火，必须敲击才会动。等到它发动时，根据人的禀质轻重而定，轻的可以不经治疗而痊愈，重的如果不是善于治疗就不能痊愈，这就是所说的“先天而天不违”。又必须根据天行之时的气候缓急而定，缓的外邪来得不猛烈，可以轻微发散，可以清热解表，随顺表达而不遗漏；重的外邪之气大多猛烈急促，正气先被其侵伐，内毒蕴结而不能发出，应当集中精力治疗其标症，使蕴结的毒素乘着势头向外透达，这就是所说的“后天而奉天时”。如果能够详尽了解先天的本体，明白后天的应用，那么周旋应对，无论到哪里都能得到中庸之道了。
When the heaven has abnormal qi out of season, humans will suffer from diseases out of season. Those with strong constitution can still overcome it with their Yuan Qi (Original Qi), but only Measles and Smallpox are unavoidable for everyone, often occurring in infants, thus becoming a common disease throughout the world. Examining the writings of ancient sages, they detailed the discussion on Smallpox but were brief on Measles, likely because Measles emerges from the Six Fu Organs, differing from Smallpox which emerges from the Five Zang Organs. If the treatment method is correct, key points can be grasped with few words. Later learners who do not understand this meaning often claim that treating Smallpox is difficult while treating Measles is easy. Through superficial attempts and light trials, many have treated human lives as if they were worthless grass, which is truly sorrowful. In the Renzi year (1852), from spring extending to summer and autumn, in both large villages and small settlements, the number of children who died prematurely was countless. Although it is said to be determined by fate, half of it is due to the physicians in charge not having grasped the essential keys. Yancheng compiled "Measles Beiyao" (Essential Preparation for Measles), collecting the refined words and good methods of the ancients, which can be used with those who understand principles to verify the source of heart-mind in treating young children. Recently, because my father acted as the printer for the book "Shenjiu Jinglun" (Classic of Divine Moxibustion), I requested to print it afterwards, and thus wrote a few words at the beginning of the volume. The time is the mid-summer month of Gui Chou year (1853) of the Xianfeng era, written by Wu Yujiu of Shuangxi in a humble and rough dwelling.
The disease of Rash (Measles) originates from fetal toxin and erupts upon contracting the epidemic pathogenic qi, similar to Smallpox. However, Smallpox emerges from the Five Zang Organs belonging to Yin; Yin governs Blood, so it has form and pus, and its symptoms include cold and heat, deficiency and excess. Measles emerges from the Six Fu Organs belonging to Yang; Yang governs Qi, so it has form but no pus, and its symptoms are mostly excess, featuring heat without cold. Since the symptoms differ, the treatment methods also differ. The world generally knows that the impact of Smallpox and Measles on people is very heavy, but does not realize that the impact of Measles on life and death is even more critical. Generally, when a person is first born, they receive the qi of Heaven and Earth to form their body. Qian (Heaven) is Yang, hence called Father; Kun (Earth) is Yin, hence called Mother. When the Qi of Yin and Yang interact, the Ministerial Fire resides within them. Therefore, the Fire within Yin lies latent in the human body, and when it erupts, it becomes Smallpox; the Fire within Yang lies latent in the human body, and when it erupts, it becomes Measles. When these have not yet erupted, there is no shape to imitate and no trace to follow, like fire in stone, which must be struck to move. Once it moves, depending on the individual's constitution, mild cases may heal without treatment, while severe cases require skilled treatment to heal; this is what is meant by "preceding Heaven, Heaven does not violate." Furthermore, one must consider the urgency of the seasonal pathogenic qi: if mild, the external pathogen arrives not violently, allowing for gentle dispersal or clearing and resolving, following the exterior expression without omission; if severe, the external pathogenic qi is violent and rapid, attacking the Righteous Qi first, causing internal toxins to accumulate and fail to erupt. Urgent effort should be focused on treating the branch manifestation, enabling the accumulated toxins to reach the exterior with momentum; this is what is meant by "following Heaven, complying with Heavenly Time." If one can fully comprehend the substance of Pre-Heaven and clarify the application of Post-Heaven, then through maneuvering and adaptation, one will find the mean wherever one goes.