凡候疹脉，自初热见形，以及收没，但看右手一指脉洪大有力，虽有杂症，亦无大
害，盖右手一指脉，太阴肺脉也。肺主皮毛，脉气通，自能载毒外出，是以无害。若肺脉
沉小无力，大非所宜，疹发于阳经，脉反沉小，是为阳症阴脉。司命者于此处最要留心，
不得谓疹症无虚寒，而固执清热解毒，以败乃事也。
症者证也，证之于外，以知其内。凡病皆然，不独疹也。疹出于脾肺二经，初必因
外感而发，与伤风伤寒无异，特其症咳嗽喷嚏，面肿腮赤，目胞浮肿，眼泪汪汪，鼻流
清涕，呵欠闷顿，乍凉乍热，手足稍冷，或中指独冷，睡时惊悸，或恶心呕哕，或以手
掐面目唇鼻，是皆出疹之候。又必发热五六日，而后见遍身红点，大者如苏子，次者如
芥子，小者如蚕子，而成粒成片者是也。麻则最细而碎，如蚊迹模糊，斑则无颗粒，惟
成片红紫，如云如锦。又有遍身但红而绝无斑点者，谓之火丹，数种亦皆疹类，大都正
疹则热至五六日而后出，则成朵成粒，非若斑疹之皮红成片也。且斑疹之出，则不拘三
日四日五日六日，出而又没，没而又出，俗谓一日三出，三日九出，只要出透，以遍身
红润者为美，最嫌黑陷，及面目胸腹稠密，缠锁咽喉者为逆。发不出而喘者即死。如伤寒
发斑，不能透发者亦危。金鉴谓麻为正疹，亦胎元之毒，故凡出疹，必须识各经中现症，如
邪气遏郁于脾，则泄泻不止，扰乱于心，则烦热不退而发惊，熏灼于肺，则呕嗽出血，移
热于肝，则目多眵泪，归结于肾，则牙龈烂而疳蚀。五脏受病既深，正气日馁而不振，若
非及早图之，鲜有不败者矣。更有不治之症，如黑黯焦枯一出即没者，气血两败也。鼻扇
口张者，脾肺气将绝也。鼻青粪黑者，脾肾垂危也。气喘心前吸者，心气已殆也。谚云∶
走马看麻痘，极言其变迁甚速，非比寻常内伤外感，可缓治以图功。
凡是诊察麻疹的脉象，从初期的发热出疹，到最后的收没消退，只要看到右手寸口脉（食指所按部位）洪大有力，即使伴有其他杂症，也不会有大的危害。这是因为右手寸口脉对应的是太阴肺经的脉象。肺主司皮毛，脉气通畅，自然能托毒邪外出，所以没有危害。如果肺脉呈现沉小无力的状态，这就非常不适宜了。麻疹发于阳经，脉象反而沉小，这属于“阳证阴脉”。医生在此处最需要留心，不能认为麻疹病症没有虚寒的情况，而固执地坚持使用清热解毒的方法，从而导致治疗失败。
“症”就是“证”，通过观察外在的表现来推断内部的病机。所有疾病都是这样，不仅仅是麻疹。麻疹源于脾、肺两经，初期必定是因为外感邪气而引发，与伤风、伤寒没有本质区别，只是其症状表现为咳嗽、打喷嚏、面部肿胀、腮部发红、眼睑浮肿、眼泪汪汪、流清鼻涕、打哈欠且精神困顿、忽冷忽热、手脚稍冷或仅中指独冷、睡眠时惊悸不安、恶心呕吐，或者用手抓挠面部嘴唇鼻子等，这些都是出疹的先兆。此外，必须经过五六天的发热，然后才出现遍布全身的红色斑点，大的像苏子（紫苏籽），小的像芥菜籽，更小的像蚕子，形成颗粒成片状的就是麻疹。麻是最细碎如蚊子叮咬痕迹般模糊的；斑则没有颗粒，只是成片红紫，像云霞锦缎一样。还有全身发红却完全没有斑点的，称为火丹，这几类也都属于疹的范畴。大体上，正疹通常是发热到五六天后才发出，呈朵状或颗粒状，不像斑疹那样皮红成片。而且斑疹的出现，不拘泥于第三、四、五、六天，可能出了又隐没，隐没了又再出，俗称“一日三出，三日九出”，只要出得透彻，以全身红润为最佳，最忌讳的是黑陷，以及面目胸腹部位稠密、缠绕锁住咽喉的，这些都属于逆证。疹发不出且伴有喘息的，立即死亡。如伤寒发斑，不能透发的，也危险。《医宗金鉴》认为麻是正疹，也是胎元之毒，所以凡是出疹，必须识别各经络中显现的症状，如邪气郁结在脾，则腹泻不止；扰乱在心，则烦热不退并引发惊厥；熏灼在肺，则呕吐咳嗽出血；移热于肝，则眼屎多流泪；归结于肾，则牙龈腐烂并发生疳蚀。五脏受病既深，正气日益衰弱而不能振奋，如果不及早谋划治疗，很少有不失败的。更有不治之症，如颜色黑黯焦枯，一出即隐没的，这是气血两败。鼻翼扇动、张口呼吸的，是脾肺气将绝。鼻孔发青、大便黑色的，是脾肾垂危。气喘且心前区吸气困难的，是心气已衰竭。谚语说：“走马看麻痘”，极言其病情变化迅速，不像普通的内伤外感，可以缓慢治疗以求功效。
When examining the pulse in measles, from the initial fever and appearance of the rash to its resolution, if the pulse at the Cun position (the first finger position) on the right hand is surging (Hong) and forceful, even if accompanied by other miscellaneous symptoms, there will be no major harm. This is because the right-hand Cun pulse corresponds to the Taiyin Lung meridian. The Lung governs the skin and hair; when the pulse Qi is unobstructed, it naturally carries the pathogenic toxins outward, thus causing no harm. If the Lung pulse appears deep (Chen), small (Xiao), and weak, this is highly inappropriate. Measles erupts in the Yang meridians, yet the pulse is instead deep and small, which constitutes a "Yang syndrome with Yin pulse." Physicians must pay utmost attention here and must not assume that measles cases lack deficiency-cold patterns, nor should they rigidly adhere to clearing heat and detoxifying methods, thereby ruining the treatment outcome.
"Zheng" (symptom/presentation) is equivalent to "Zheng" (syndrome). Observing the external manifestations allows one to understand the internal pathology. This applies to all diseases, not just measles. Measles originates from the Spleen and Lung meridians. Initially, it is triggered by external pathogenic invasion, similar to wind-cold or cold damage, but distinguished by symptoms such as coughing, sneezing, facial swelling, reddened cheeks, swollen eyelids, watery eyes, clear nasal discharge, yawning with lethargy, alternating chills and fever, slightly cold extremities or specifically only the middle finger being cold, palpitations during sleep, nausea, vomiting, or scratching the face, lips, and nose. These are all prodromal signs of measles. Furthermore, after five to six days of fever, red spots appear all over the body. Those large are like pericarpium Sinapis albae (white mustard seed), those medium-sized are like semen Sinapis albae (white mustard seed), and those small are like bombyx batryticatus (silkworm feces); forming granular patches characterizes true measles. "Ma" (measles/rubella-like) is the finest and fragmented, resembling blurred mosquito bites. "Ban" (macules/scarlet fever-like) has no granules, appearing only as continuous red-purple patches, like clouds or brocade. There are also cases where the whole body is merely red without any spots, called Huodan (fire erysipelas); these several types all belong to the category of rashes. Generally, true measles erupts after five to six days of fever, forming clusters or granules, unlike Ban-rash which presents as continuous red skin patches. Moreover, the eruption of Ban-rash is not confined to the third, fourth, fifth, or sixth day; it may emerge and disappear repeatedly, colloquially described as "three eruptions in one day, nine in three days." As long as the eruption is thorough, with a rosy-red complexion all over the body, it is considered auspicious. The most ominous signs are black depression, dense eruptions on the face, eyes, chest, and abdomen, and constriction around the throat, which are termed adverse conditions. If the rash fails to erupt and is accompanied by asthma/dyspnea, death ensues immediately. Similarly, in cold damage with macules, failure to erupt thoroughly is critical. *Yizong Jinjian* states that Ma is the true rash, representing fetal toxicity. Therefore, in all measles cases, one must identify the manifestations associated with each meridian. For instance, if pathogenic qi stagnates in the Spleen, diarrhea persists; if it disturbs the Heart, irritability and fever persist leading to convulsions; if it scorches the Lungs, vomiting, coughing, and hemoptysis occur; if heat shifts to the Liver, excessive eye discharge and tearing result; if it resolves in the Kidneys, gum rot and gan-erosion develop. Once the Five Zang organs are deeply affected, the healthy Qi declines daily and fails to revive. Without early intervention, few cases succeed. There are also incurable syndromes: if the color is dark-black and scorched-dry, disappearing immediately upon eruption, this indicates exhaustion of both Qi and Blood. Nasal flaring and open-mouth breathing indicate impending exhaustion of Spleen and Lung Qi. Blue nostrils and black stool indicate critical failure of Spleen and Kidney. Asthma with precordial suction indicates depletion of Heart Qi. The proverb says, "Watch measles and smallpox as fast as a running horse," emphasizing their rapid changes, unlike ordinary internal injury or external invasion, which allow for slow treatment to achieve results.