既视其唇。当察唇之四白。四白者。口唇四际之白色也。考之内经。督脉至人中。任脉至承浆。冲脉络唇口。
足阳明之脉。挟口环唇。手阳明之脉。挟口交人中。经曰。脾胃大肠小肠三焦膀胱者。仓廪之本。营之居也。
其华在唇四白。其充在肌。其味甘。其色黄。此至阴之类。通于土气。故五阅五使篇曰。口唇者。脾之官也。以
部位言之。上为阳。下为阴。左为阳。右为阴。察其色之上下左右。可辨其病之上下左右也。青赤黄白黑五
色。合之五行。应乎五脏也。太过者。病在外。不及者。病在内。腑主乎外。脏主乎内也。于是乎有泽夭之分焉。
所以辨其成败也。有浮沉清浊之分焉。所以辨其表里阴阳也。有微甚散抟之分焉。所以辨其虚实久新
也。以五色相应之理推之。其病症可知也。以五行生克之理推之。其顺逆可知也。以气色部位合而推之。
其脏腑相乘之理又可知也。经云。五脏六腑。固尽有部。视其五色。黄赤为热。白为寒。青黑为痛。此所谓视
而可见者也。千金云。病患鼻下平者。胃病也。微赤者。病发痈。微黑者有热。青者有寒。白者不治。唇黑者胃
先病。微燥而渴者可治。不渴者不可治。此皆诊色之要也。若合四诊而观之。参四时而辨之。推之无穷。用之不尽矣。
盖闻上曰齿。下曰牙。两旁曰牙。当中曰齿。然齿者。总谓口中之骨。主 啮者也。家语曰。男子八月生齿。八
岁而 。女子七月生齿。七岁而 。盖齿者。骨之所终也。经言丈夫八岁齿更。三八真牙生。七八齿槁。女子
七岁齿更。三七真牙生。七七齿槁。夫齿之为言。始也。年也。肾之标。骨之余也。少长别乎此。盛衰见乎此也。
以形言。则齿食多长也。食少者幼也。以色言。则齿色黄者长也。色白者幼也。是皆长幼之常。非疾病之变
也。及其病而察其变。则又有提纲焉。一曰形容之变。二曰气色之变。察其滋润干燥。可知病之寒热。察其
枯槁明亮。可决病之死生。形容之变者。切牙为邪入于胃。 齿为风入其经。下齿龋者手阳明。上齿龋者
足太阳。长而枯者。骨先绝。脱而落者。症多凶。气色之变者。齿忽黄。为肾虚。齿忽黑。为肾热。滋润者。津液犹
充。干燥者。津液已耗。形色枯槁者。精气将竭。形色明亮者。精气未衰。析而言之。互而观之。合五官。参四诊。
而吉凶之辨。虚实之分。了然如指掌矣。若夫牙龈形色。当以肿起为实。陷下为虚。深赤为太过。淡红为不
及。可与诊唇之法。比例而推也。
已经观察了嘴唇，就应当考察唇四白的情况。所谓“唇四白”，是指口唇四周呈现白色的区域。查阅《内经》记载：督脉到达人中穴，任脉到达承浆穴，冲脉络属口唇，足阳明胃经挟持口部环绕嘴唇，手阳明大肠经挟持口部交于人中穴。经文说：“脾胃、大肠、小肠、三焦、膀胱，是仓廪之本，营气所居之处。”它们的荣华表现于唇四白，充养在肌肉，味道对应甘味，颜色对应黄色，这属于至阴的一类，与土气相通。所以《灵枢·五阅五使篇》说：“口唇是脾的外候。”从部位来说，上部为阳，下部为阴；左侧为阳，右侧为阴。观察颜色的上下左右变化，可以辨别病变部位的上下左右。青、赤、黄、白、黑五色，合应五行，对应五脏。色太过，病在体表（外）；色不及，病在体内（内）。腑病主外，脏病主内。因此有润泽与枯夭的区别，用来辨别病情的成败。有浮沉、清浊的区别，用来辨别表里阴阳。有微甚、散抟（聚结）的区别，用来辨别虚实的病程久新。根据五色相应的道理推演，病症就可以知道了。根据五行生克的道理推演，顺逆关系就可以知道了。将气色与部位结合推演，脏腑相乘的道理也可以知道了。经文说：“五脏六腑，本来都有对应的部位，观察五色，黄赤色主热，白色主寒，青色和黑色主痛。”这就是所谓的“视而可见”的诊断方法。《千金方》说：“病人鼻下平坦的，是胃病。微微发红的，病发痈肿。微微发黑的，有热。发青的，有寒。发白的，难以治愈。嘴唇发黑的，胃先受病。如果微燥且口渴的可以治，不口渴的不可治。”这些都是诊察面色要点。如果结合望闻问切四诊来观察，参考四季气候变化来辨别，其道理无穷无尽，应用不尽。
听说上面叫齿，下面叫牙，两旁叫牙，当中叫齿。然而“齿”总称口中的骨头，主要功能是咀嚼。《孔子家语》说：“男子八月长牙，八岁换牙。女子七月长牙，七岁换牙。”大概齿是骨的终末表现。经文说：男子八岁换牙，三八二十四岁真牙（智齿）生出，七八五十六岁牙齿干枯。女子七岁换牙，三七二十一岁真牙生出，七七四十九岁牙齿干枯。齿这个字，意为开始，也指年龄。它是肾的外标，是骨的余气。老少区别于此，盛衰显现于此。从形态来说，牙齿多且长的说明年长，少且小的说明年幼。从颜色来说，牙齿色黄的说明年长，色白的说明年幼。这些都是长幼的正常现象，不是疾病的变象。等到生病时观察其变化，又有提纲可循。一是形态的变化，二是气色的变化。观察滋润或干燥，可以知道病的寒热；观察枯槁或明亮，可以决断病情的死生。形态的变化方面：咬牙是邪气入胃，啮齿（磨牙）是风邪入经。下齿龋坏属于手阳明大肠经，上齿龋坏属于足太阳膀胱经。牙齿长但干枯的，说明骨气先绝；牙齿脱落掉的，病情多凶险。气色的变化方面：牙齿忽然变黄，是肾虚；牙齿忽然变黑，是肾热。滋润的，说明津液尚充足；干燥的，说明津液已耗损。形色枯槁的，说明精气将竭；形色明亮的，说明精气未衰。详细分析，互相参照，结合五官观察，参合四诊，那么吉凶的辨别、虚实的区分，就会像指手掌一样清楚明了。至于牙龈的形色，应当以肿胀突起为实证，凹陷低下为虚证，深红色为太过，淡红色为不及，可以与诊断嘴唇的方法类比推演。
Having observed the lips, one must examine the *Chun Sibai* (Lip Four Whites, the white area surrounding the lips). The term "Chun Sibai" refers to the whitish hue found at the four margins of the lips. Consulting the *Neijing* (Classic of Internal Medicine), it is recorded that the Du Meridian reaches the Renzhong point, the Ren Meridian reaches the Chengjiang point, the Chong Meridian connects with the lips and mouth, the Foot-Yangming Stomach Meridian flanks the mouth and encircles the lips, and the Hand-Yangming Large Intestine Meridian flanks the mouth and intersects at the Renzhong point. The classics state: "The Spleen, Stomach, Large Intestine, Small Intestine, Sanjiao, and Bladder are the root of the granaries and the residence of Ying Qi (Nutritive Qi)." Their flourishing manifestation appears in the Chun Sibai, their nourishment lies in the muscles, they correspond to the Pungent flavor (Note: Text says Gan/Sweet, but standard TCM theory links Spleen/Stomach to Sweet/Gan. Text says "Qi Wei Gan", I will translate as Sweet/Pungent based on text "Gan"), and their color corresponds to Yellow. This belongs to the category of Supreme Yin and communicates with Earth Qi. Therefore, the chapter "Wu Yue Wu Shi" states: "The mouth and lips are the official organ of the Spleen." From a positional perspective, the upper part is Yang, the lower part is Yin; the left is Yang, the right is Yin. By observing the colors above, below, to the left, and to the right, one can distinguish the location of the disease above, below, left, or right. The five colors—Green, Red, Yellow, White, and Black—correspond to the Five Elements and match the Zang Organs. Excess indicates disease in the exterior; deficiency indicates disease in the interior. Fu Organs govern the exterior, while Zang Organs govern the interior. Thus, there is a distinction between luster/vitality and withering/despair, used to differentiate success or failure in prognosis. There is a distinction between floating/sinking and clear/turbid, used to differentiate exterior/interior and Yin/Yang. There is a distinction between slight/severe and dispersed/aggregated, used to differentiate deficiency/excess and chronic/new onset. By deducing from the principle of corresponding five colors, the symptoms can be known. By deducing from the principles of generation and restriction among the Five Elements, the favorable or unfavorable course can be known. By combining qi-color and position for deduction, the principles of Zang-Fu mutual overacting can also be known. The classics say: "The Five Zang and Six Fu organs inherently have specific locations. Observing the five colors: Yellow and Red indicate Heat; White indicates Cold; Green and Black indicate Pain." This is what is called "visible upon inspection." The *Qianjin Fang* states: "If the area below the nose is flat, it indicates Stomach disease. Slightly red indicates the onset of an abscess. Slightly black indicates Heat. Green indicates Cold. White indicates untreatable conditions. Black lips indicate prior Stomach disease. If slightly dry and thirsty, it is treatable; if not thirsty, it is untreatable." These are all essential points of complexion diagnosis. If combined with observation, listening/smelling, inquiry, and palpation, and analyzed in reference to the four seasons, the principles are inexhaustible and applications endless.
It is heard that teeth in the upper jaw are called "Chi," those in the lower jaw are called "Ya," those on the sides are "Ya," and those in the middle are "Chi." However, "Chi" generally refers to the bones in the mouth, primarily responsible for mastication. The *Kongzi Jiayu* states: "Males grow teeth at eight months and replace them at eight years. Females grow teeth at seven months and replace them at seven years." Generally, teeth are the culmination of bone structure. The classics state: Males replace teeth at age eight, true teeth (molars) emerge at 3x8=24, and teeth wither at 7x8=56. Females replace teeth at age seven, true teeth emerge at 3x7=21, and teeth wither at 7x7=49. The character "Chi" implies beginning and age. It is the external marker of the Kidney and the remnant of bone. Distinctions between young and old are made here; manifestations of vigor and decline appear here. In terms of form, many and long teeth indicate maturity; few and small teeth indicate youth. In terms of color, yellowish teeth indicate maturity; white teeth indicate youth. These are normal variations of aging, not pathological changes. When disease occurs and changes are observed, there are guiding principles. First, changes in appearance; second, changes in qi-color. Observing moisture or dryness reveals Cold or Heat; observing withered/bright states determines life or death prognosis. Regarding appearance changes: grinding teeth indicates pathogenic factors entering the Stomach; gnashing teeth indicates Wind invading the meridians. Lower tooth decay relates to the Hand-Yangming Large Intestine Meridian; upper tooth decay relates to the Foot-Taiyang Bladder Meridian. Teeth that are long but withered indicate exhaustion of Bone Qi first; teeth that fall out indicate a ominous prognosis. Regarding qi-color changes: sudden yellowing of teeth indicates Kidney Deficiency; sudden blackening indicates Kidney Heat. Moisture indicates sufficient Body Fluids; dryness indicates depletion of Body Fluids. Withered form and color indicate impending exhaustion of Essence-Qi; bright form and color indicate un-depleted Essence-Qi. Analyzed in detail and viewed mutually, combined with the five sensory organs and the four diagnostic methods, the differentiation of auspicious/inauspicious and deficiency/excess becomes as clear as looking at one's palm. As for the gums' form and color, swelling and protrusion indicate Excess, while depression and sinking indicate Deficiency; deep red indicates excessiveness, while pale red indicates insufficiency. These can be deduced by analogy with the methods for diagnosing the lips.