景岳子曰∶痘之与疹原非一种。虽痘之变态多证，而疹之收敛稍易。然疹之甚者，其势
凶危亦不减于痘。最为可畏盖疹毒痘毒本无异也。第古人重痘而忽疹，多不详及，使后人
无所宗法，余实怅之。自得罗田万氏之刻，见其理透法精，鄙念斯慰。今悉从其训，备述于
此，虽其中稍有裁订，亦不过正其疑似，详其未详耳。使此后患疹者幸获迷津之指南，亦以见万氏之功为不少矣。
疹者痘之末疾，惟二经受证，脾与肺也。内应于手足太阴，外合于皮毛肌肉，是皆天地
间戾不正气，故曰疹也。（音同疠）然其名目有异，在苏松曰痧子，在浙江曰 子，（音同
错）又曰 子，在江右湖广广东安徽曰麻子，在山陕曰籽疮，曰糠疮，曰赤疮，在北直曰疹
子，（音同轸）名虽不同其证则一。但疹在痘前者，痘后必复出疹，惟痘后出疹者，方为正疹结局。
万氏曰∶疹以春夏为顺，秋冬为逆。以其出于脾肺二经，一遇风寒，势必难出，且多变
证，故于秋冬为不宜耳。夫天行不正之气，致为人之疡疹。然古人于痘、疹二字始终归重于
痘，并不分别。疹为何物，岂可以二证归于一证耶。想当时重痘不重疹，故尔略之，致使后
人不得心法，因而害事者往往有之。今以吾家四代传流，以及今日心得之法开载于后，用此
应治，定不瘥矣。敢有毫厘隐秘，天其鉴之。
张景岳说：痘疮与麻疹原本不是同一种疾病。虽然痘疮的变证较多，但麻疹的收敛（恢复）相对容易。然而，严重的麻疹，其病势凶险程度也不亚于痘疮。最让人畏惧的是，疹毒和痘毒本质上并没有区别。只是古人重视痘疮而轻视麻疹，大多没有详细论述，导致后人没有遵循的法度，我对此感到遗憾。自从得到罗田万氏刻印的书籍后，看到其中医理透彻、治法精妙，我的忧虑才得以安慰。现在完全遵循他的教导，在此详细叙述，虽然其中稍有裁量修订，也不过是纠正似是而非之处，补充未详尽的内容罢了。希望此后患麻疹的人能幸运地获得迷途中的指南，这也足以显示万氏的功劳不小了。
麻疹是痘疮的末疾（伴随或后续病症），主要涉及脾经和肺经这两条经络。在体内对应手足太阴经（手太阴肺经、足太阴脾经），在体外合于皮毛肌肉，这些都是天地间不正的戾气所致，所以称为疹。（读音同“疠”）然而它的名称各异，在苏州、松江地区称为痧子，在浙江称为㿉子（读音同“错”），又称为㿉子，在江西、湖广、广东、安徽地区称为麻子，在山陕地区称为籽疮、糠疮、赤疮，在北直隶地区称为疹子（读音同“轸”）。名称虽然不同，但证候是一样的。但是，如果在出痘之前出疹，那么出痘后必定会再次出疹；只有出痘之后才出疹的，才是正疹的结局。
万氏说：麻疹以春夏季节出现为顺证，秋冬季节出现为逆证。因为麻疹发源于脾肺二经，一旦遇到风寒，势必难以透发，且容易变化出其他证候，所以在秋冬季节是不适宜的。这种天行不正之气，导致人体发生疡疹。然而古人在痘、疹二字上，始终将重点归于痘疮，并不加以区分。麻疹究竟是什么？怎么能将两种证候归为一种呢？想当时重视痘疮而不重视麻疹，所以对此略而不谈，致使后人得不到心法，因而造成危害的事情往往有之。现在将我家族四代传承以及今日心得的方法记载在后面，用此来应对治疗，一定能够痊愈。若有丝毫隐瞒，上天将鉴察之。
Zhang Jingyue stated: Smallpox (Dou) and measles (Zhen) are originally not the same disease. Although smallpox presents with more varied syndromes, measles is slightly easier to resolve (recover). However, severe cases of measles can be equally perilous in their progression as smallpox. What is most feared is that the toxin of measles and the toxin of smallpox are essentially no different. It is merely that ancient physicians valued smallpox while neglecting measles, rarely discussing it in detail, leaving later generations without a standard to follow, which I truly regretted. Since obtaining the printed work by Master Wan from Luotian, seeing its profound principles and refined methods, my concerns were alleviated. Now, fully adhering to his teachings, I elaborate here. Although there are slight adjustments, they serve only to correct ambiguities and detail what was previously omitted. May those who suffer from measles in the future find guidance through this confusion, thereby acknowledging the significant merit of Master Wan.
Measles is considered a terminal ailment related to smallpox, primarily manifesting in the Spleen and Lung meridians. Internally, it corresponds to the Hand-Taiyin (Lung) and Foot-Taiyin (Spleen) meridians; externally, it combines with the skin, hair, muscles, and flesh. These are caused by malignant and abnormal Qi (vital energy) in heaven and earth, hence it is called Zhen (pronounced similarly to "Li," meaning pestilence). However, its names vary: in Suzhou and Songjiang, it is called Shazi; in Zhejiang, it is called Lizi (pronounced similarly to "Cuo") or Lizi; in Jiangxi, Huguang, Guangdong, and Anhui, it is called Mazzi; in Shanxi and Shaanxi, it is called Zichuang, Kangchuang, or Chichuang; in Zhili, it is called Zhenzi (pronounced similarly to "Zhen"). Although the names differ, the syndromes are identical. If rash appears before smallpox, smallpox will inevitably reappear after the initial eruption; only when rash appears after smallpox does it constitute the proper conclusion of measles.
Master Wan stated: Measles appearing in spring and summer is favorable (Shun), while appearing in autumn and winter is unfavorable (Ni). Since it originates from the Spleen and Lung meridians, once exposed to wind-cold, it becomes difficult to erupt and prone to complicated syndromes, making autumn and winter unsuitable seasons for its appearance. This abnormal atmospheric Qi causes ulcers and rashes in humans. However, ancients consistently emphasized smallpox over measles, failing to distinguish between them. What exactly is measles? How can two distinct conditions be merged into one? It seems that due to valuing smallpox over measles at that time, it was overlooked, causing later generations to miss the essential methods, leading to frequent harm. Now, recording the four generations of family transmission along with my own insights for future reference, using these methods for treatment ensures recovery. If I conceal even a slightest detail, may Heaven witness it.